1 00:00:00,137 --> 00:00:03,002 We humans have known for thousands of years, 2 00:00:03,002 --> 00:00:05,867 just looking at our environment around us, 3 00:00:05,867 --> 00:00:07,207 that there're different substances. 4 00:00:07,207 --> 00:00:10,333 These different substances...tend to have different properties. 5 00:00:10,333 --> 00:00:11,954 Not only do they have different properties; 6 00:00:11,954 --> 00:00:14,745 one might reflects light in a certain way, or not reflect light. 7 00:00:14,745 --> 00:00:17,601 Or be a certain color, or be have a certain temperature; 8 00:00:17,601 --> 00:00:20,457 be liquid, or gas or be a solid. 9 00:00:20,457 --> 00:00:22,108 But we also start to observe 10 00:00:22,108 --> 00:00:24,867 how they react with each other in certain circumstances. 11 00:00:24,867 --> 00:00:27,663 and here's pictures of some of these substances. 12 00:00:27,663 --> 00:00:31,477 This right here is carbon, and this is in the...in its graphite form 13 00:00:31,477 --> 00:00:36,069 This right here is lead; this right here is gold 14 00:00:36,069 --> 00:00:38,719 and all of the ones that I've drawn, that I've shown pictures of here, 15 00:00:38,719 --> 00:00:41,369 I got them all from this website right over there 16 00:00:41,369 --> 00:00:45,453 All of these are in their solid form, but we also know that we... 17 00:00:45,453 --> 00:00:47,395 It looks like there's certain types of air in it, 18 00:00:47,395 --> 00:00:49,338 certain types of air particles, 19 00:00:49,338 --> 00:00:52,210 and depending on what type of air particles you're looking at 20 00:00:52,210 --> 00:00:55,079 whether it is carbon, or oxygen, or nitrogen, 21 00:00:55,079 --> 00:00:57,948 that seems to have different types of properties. 22 00:00:57,948 --> 00:00:59,425 Or, there are some other things that can be liquid, 23 00:00:59,425 --> 00:01:02,082 or even if you raise the temperature high enough on these things. 24 00:01:02,082 --> 00:01:05,018 If you raise the temperature high enough on gold or lead, 25 00:01:05,018 --> 00:01:06,503 you could get a liquid. 26 00:01:06,503 --> 00:01:09,841 Or if you kind of -- if you burn this carbon, 27 00:01:09,841 --> 00:01:12,076 you can get it to a gaseous state, 28 00:01:12,076 --> 00:01:13,351 you can release it into the atmosphere, 29 00:01:13,351 --> 00:01:14,702 you can break its structure. 30 00:01:14,702 --> 00:01:17,271 So these are things that we've all kind of 31 00:01:17,271 --> 00:01:20,585 that humanity has observed for thousands of years. 32 00:01:20,585 --> 00:01:22,452 But that leads to a natural question 33 00:01:22,452 --> 00:01:24,226 that used to be a philosophical question, 34 00:01:24,226 --> 00:01:26,405 but now we can answer it a little bit better, 35 00:01:26,405 --> 00:01:30,898 and that question is, if you keep breaking down this carbon 36 00:01:30,898 --> 00:01:33,518 into smaller and smaller chunks, 37 00:01:33,518 --> 00:01:35,554 if there's some smallest chunk, 38 00:01:35,554 --> 00:01:39,867 some smallest unit of this stuff, of this substance 39 00:01:39,867 --> 00:01:43,166 that still has the properties of carbon? 40 00:01:43,166 --> 00:01:45,256 And if you were to somehow break that down even further, 41 00:01:45,256 --> 00:01:48,390 you would lose the properties of the carbon? 42 00:01:48,390 --> 00:01:50,354 And the answer is: there is. 43 00:01:50,354 --> 00:01:52,200 And so just to get our terminology, 44 00:01:52,200 --> 00:01:56,156 we call these different substances, that these pure substances 45 00:01:56,156 --> 00:01:59,025 that have these specific properties at certain temperatures, 46 00:01:59,025 --> 00:02:01,185 and react in certain ways, 47 00:02:01,185 --> 00:02:05,291 we call them elements. 48 00:02:05,291 --> 00:02:08,729 Carbon is an element. Lead is an element. Gold is an element. 49 00:02:08,729 --> 00:02:10,400 You might say that water is an element. 50 00:02:10,400 --> 00:02:14,221 And in history, people have referred to water as an element. 51 00:02:14,221 --> 00:02:17,892 But now we know that water is made up of more basic elements. 52 00:02:17,892 --> 00:02:20,405 It's made of oxygen and of hydrogen. 53 00:02:20,405 --> 00:02:25,014 And all of our elements are listed here 54 00:02:25,014 --> 00:02:27,758 in the periodic table of elements. 55 00:02:27,758 --> 00:02:29,374 C stands for carbon 56 00:02:29,374 --> 00:02:30,400 -- I'm just going through the ones 57 00:02:30,400 --> 00:02:32,379 that are very relevant to humanity -- 58 00:02:32,379 --> 00:02:35,502 but over time you'll probably familiarize yourself with all of these. 59 00:02:35,502 --> 00:02:39,148 This is oxygen. This is nitrogen. This is silicon. 60 00:02:39,148 --> 00:02:42,867 This is -- Au is gold. This is lead. 61 00:02:42,867 --> 00:02:51,995 And that most basic unit of any of these elements is the atom. 62 00:02:51,995 --> 00:02:54,559 So if you were to keep digging in 63 00:02:54,559 --> 00:02:57,079 and keep taking smaller and smaller chunks of this. 64 00:02:57,079 --> 00:02:59,415 Eventually you would get to a carbon atom. 65 00:02:59,415 --> 00:03:00,755 Do the same thing over here, 66 00:03:00,755 --> 00:03:02,536 eventually you'd get to a gold atom. 67 00:03:02,536 --> 00:03:03,991 You did the same thing over here, 68 00:03:03,991 --> 00:03:05,856 eventually you'd get some of this little small 69 00:03:05,856 --> 00:03:07,758 -- for a lack of a better word -- particle, 70 00:03:07,758 --> 00:03:09,185 that you'd call a lead atom. 71 00:03:09,185 --> 00:03:11,239 And you wouldn't be able to break that down anymore 72 00:03:11,239 --> 00:03:13,597 and still call that lead, 73 00:03:13,597 --> 00:03:17,043 for it still have the properties of lead. 74 00:03:17,043 --> 00:03:18,330 And just to give you an idea 75 00:03:18,330 --> 00:03:21,193 -- this is really something that I have trouble imagining -- 76 00:03:21,193 --> 00:03:24,040 is that atoms are unbelievably small. 77 00:03:24,040 --> 00:03:25,901 Really, unimaginably small. 78 00:03:25,901 --> 00:03:27,555 So for example, carbon. 79 00:03:27,555 --> 00:03:29,379 My hair is also made out of carbon. 80 00:03:29,379 --> 00:03:31,882 In fact most of me is made out of carbon. 81 00:03:31,882 --> 00:03:35,912 In fact most of all living things are made out of carbon. 82 00:03:35,912 --> 00:03:40,533 And so if you took my hair. And so my hair is carbon. 83 00:03:40,533 --> 00:03:42,231 My hair is mostly carbon. 84 00:03:42,231 --> 00:03:43,989 So if you took my hair right over here 85 00:03:43,989 --> 00:03:45,565 -- my hair isn't yellow 86 00:03:45,565 --> 00:03:46,766 but it contrasts nicely with the black. 87 00:03:46,766 --> 00:03:47,950 My hair is black. But if I did that, 88 00:03:47,950 --> 00:03:49,713 you wouldn't be able to see it on the screen. 89 00:03:49,713 --> 00:03:51,970 But if you took my hair here, I would have asked you 90 00:03:51,970 --> 00:03:55,200 how many carbon atoms wide is my hair? 91 00:03:55,200 --> 00:03:58,467 So if you took a cross-section of my hair, not the length, 92 00:03:58,467 --> 00:04:00,361 the width of my hair, and said: 93 00:04:00,361 --> 00:04:03,255 how many carbon atoms wide is that? 94 00:04:03,255 --> 00:04:07,049 And you might guess, oh, Sal already told me, it's very small, 95 00:04:07,049 --> 00:04:09,150 so maybe there's a thousand carbon atoms there, 96 00:04:09,150 --> 00:04:10,484 or ten thousand, or a hundred thousands, 97 00:04:10,484 --> 00:04:11,788 and I would say, no! 98 00:04:11,788 --> 00:04:14,249 There are one million carbon atoms. 99 00:04:14,249 --> 00:04:17,439 Or you could string one million carbon atoms 100 00:04:17,439 --> 00:04:20,933 across the width of the average human hair. 101 00:04:20,933 --> 00:04:22,585 And that's obviously an approximation, 102 00:04:22,585 --> 00:04:24,026 it's not exactly one million, 103 00:04:24,026 --> 00:04:26,605 but that gives you a sense of how small an atom is. 104 00:04:26,605 --> 00:04:28,441 You know, pluck a hair out of your head 105 00:04:28,441 --> 00:04:30,991 and just imagine putting a million things 106 00:04:30,991 --> 00:04:33,991 next to each other across the hair, 107 00:04:33,991 --> 00:04:37,037 not the length of the hair, the width of the hair. 108 00:04:37,037 --> 00:04:39,175 It's even hard to see the width of hair. 109 00:04:39,175 --> 00:04:40,718 And there would be a million carbon atoms 110 00:04:40,718 --> 00:04:42,979 just going along it. 111 00:04:42,979 --> 00:04:48,092 Now it would be pretty cool in and of itself 112 00:04:48,092 --> 00:04:49,026 -- we do know that 113 00:04:49,026 --> 00:04:51,375 there is this most basic building block of carbon, 114 00:04:51,375 --> 00:04:53,933 this most basic building block of any element. 115 00:04:53,933 --> 00:04:55,952 But what's even neater is that 116 00:04:55,952 --> 00:04:59,066 those basic building blocks are related to each other. 117 00:04:59,066 --> 00:05:02,556 A carbon atom is made of even more fundamental particles. 118 00:05:02,556 --> 00:05:07,469 A gold atom is made up of even more fundamental particles. 119 00:05:07,469 --> 00:05:10,445 And they are actually defined by 120 00:05:10,445 --> 00:05:12,759 the arrangement of those fundamental particles. 121 00:05:12,759 --> 00:05:14,087 And if you were to change 122 00:05:14,087 --> 00:05:15,901 the number of fundamental particles you have. 123 00:05:15,901 --> 00:05:17,844 You could change the properties of that element, 124 00:05:17,844 --> 00:05:18,891 how it would react, 125 00:05:18,891 --> 00:05:22,769 or you could even change the element itself. 126 00:05:22,769 --> 00:05:25,144 And just to understand it a little bit better. 127 00:05:25,144 --> 00:05:28,010 Let's talk about those fundamental elements. 128 00:05:28,010 --> 00:05:31,825 So you have the proton. 129 00:05:31,825 --> 00:05:35,524 And the proton is actually the defining 130 00:05:35,524 --> 00:05:38,003 -- the number of protons in the nucleus of an atom 131 00:05:38,003 --> 00:05:40,096 and I'll talk about the nucleus in a second -- 132 00:05:40,096 --> 00:05:42,969 that is what defines the element. 133 00:05:42,969 --> 00:05:45,492 So this is what defines an element. 134 00:05:45,492 --> 00:05:47,333 When you look at the periodic table right here, 135 00:05:47,333 --> 00:05:50,154 they are actually written in order of atomic number, 136 00:05:50,154 --> 00:05:51,575 and the atomic number is 137 00:05:51,575 --> 00:05:54,667 literally just the number of protons in the element. 138 00:05:54,667 --> 00:05:58,667 So by definition, hydrogen has 1 proton. 139 00:05:58,667 --> 00:06:02,800 Helium has 2 protons. Carbon has 6 protons. 140 00:06:02,800 --> 00:06:05,333 You cannot have carbon with 7 protons. 141 00:06:05,333 --> 00:06:07,172 If you did, it would be nitrogen, 142 00:06:07,172 --> 00:06:09,234 It would not be carbon anymore. 143 00:06:09,234 --> 00:06:10,589 Oxygen has 8 protons. 144 00:06:10,589 --> 00:06:12,673 If somehow you were to add another proton to there, 145 00:06:12,673 --> 00:06:14,050 it wouldn't be oxygen anymore. 146 00:06:14,050 --> 00:06:18,333 It would be fluorine. So it defines the element. 147 00:06:18,333 --> 00:06:20,067 It defines the element. 148 00:06:20,067 --> 00:06:22,967 And the atomic number, the number of protons, 149 00:06:22,967 --> 00:06:25,447 the number of protons -- and remember, 150 00:06:25,447 --> 00:06:27,674 that's the number that's written right at the top here 151 00:06:27,674 --> 00:06:30,116 for each of these elements in the periodic table 152 00:06:30,116 --> 00:06:31,529 -- the number of protons 153 00:06:31,529 --> 00:06:34,133 is equal to the atomic number. 154 00:06:34,133 --> 00:06:36,852 Is equal to the atomic number. 155 00:06:36,867 --> 00:06:38,861 And they put that number up here because that is 156 00:06:38,861 --> 00:06:42,221 the defining characteristic of an element. 157 00:06:42,221 --> 00:06:46,133 The other two constituents of an atom 158 00:06:46,133 --> 00:06:47,702 -- I guess we could call it that way -- 159 00:06:47,702 --> 00:06:55,123 are the electron and the neutron. 160 00:06:55,123 --> 00:06:57,541 And the model you can start to build in your head 161 00:06:57,541 --> 00:07:00,420 -- and this model, as we go through chemistry we'll see, 162 00:07:00,420 --> 00:07:02,833 it will get a little bit more abstract 163 00:07:02,833 --> 00:07:04,821 and really hard to conceptualize -- 164 00:07:04,821 --> 00:07:06,548 but one way to think about it is 165 00:07:06,548 --> 00:07:08,348 you have the protons and the neutrons 166 00:07:08,348 --> 00:07:09,825 that are the center of the atom. 167 00:07:09,825 --> 00:07:11,600 They are the nucleus of the atom. 168 00:07:11,600 --> 00:07:14,867 So for example, carbon, we know, has 6 protons. 169 00:07:14,867 --> 00:07:19,067 So one, two, three, four, five, six. 170 00:07:19,067 --> 00:07:22,385 Carbon 12, which is a version of carbon, 171 00:07:22,385 --> 00:07:24,200 will also have 6 neutrons. 172 00:07:24,200 --> 00:07:25,748 You can have versions of carbon 173 00:07:25,748 --> 00:07:28,021 that have a different number of neutrons. 174 00:07:28,021 --> 00:07:30,113 So the neutrons can change, the electrons can change, 175 00:07:30,113 --> 00:07:31,733 you can still have the same element. 176 00:07:31,733 --> 00:07:33,267 The protons can't change. 177 00:07:33,267 --> 00:07:35,905 You change the protons, you got a different element. 178 00:07:35,905 --> 00:07:39,200 So let me draw a carbon 12 nucleus. 179 00:07:39,200 --> 00:07:43,200 So one, two, three, four, five, six. 180 00:07:43,200 --> 00:07:46,487 So this right here is the nucleus of carbon 12. 181 00:07:46,487 --> 00:07:48,333 And sometimes it will be written like this. 182 00:07:48,333 --> 00:07:51,132 And sometimes they will actually write 183 00:07:51,132 --> 00:07:53,831 the number of protons as well. 184 00:07:53,831 --> 00:07:56,133 And the reason why we write it carbon 12 185 00:07:56,133 --> 00:07:58,677 -- you know I counted out 6 neutrons -- 186 00:07:58,677 --> 00:08:00,379 is that this is the total 187 00:08:00,379 --> 00:08:03,675 you could view this as the total number of 188 00:08:03,675 --> 00:08:04,741 -- one way to view it, 189 00:08:04,741 --> 00:08:06,405 and we'll get a little bit of nuance in the future 190 00:08:06,405 --> 00:08:07,770 -- is that this is the total number 191 00:08:07,770 --> 00:08:11,844 of protons and neutrons inside of its nucleus. 192 00:08:11,844 --> 00:08:15,240 And this carbon by definition has an atomic number of 6, 193 00:08:15,240 --> 00:08:16,628 but we can rewrite it here 194 00:08:16,628 --> 00:08:18,596 just so that we can remind ourselves. 195 00:08:18,596 --> 00:08:21,342 So at the center of the carbon atom we have this nucleus. 196 00:08:21,342 --> 00:08:24,863 And carbon 12 will have 6 protons and 6 neutrons. 197 00:08:24,863 --> 00:08:27,495 Another version of carbon, carbon 14, will still have 198 00:08:27,495 --> 00:08:30,909 6 protons, but then it would have 8 neutrons. 199 00:08:30,909 --> 00:08:32,467 So the number of neutrons can change, 200 00:08:32,467 --> 00:08:34,610 but this is carbon 12 right over here. 201 00:08:34,610 --> 00:08:36,842 And if carbon 12 is neutral -- 202 00:08:36,842 --> 00:08:40,665 and I'll give a little nuance on this word in a second as well -- 203 00:08:40,665 --> 00:08:43,200 if it's neutral it will also have 6 electrons. 204 00:08:43,200 --> 00:08:45,400 So let me draw those 6 electrons. 205 00:08:45,400 --> 00:08:49,467 One, two, three, four, five, six. 206 00:08:49,467 --> 00:08:51,836 And one way -- and this is maybe the first order way 207 00:08:51,836 --> 00:08:54,634 of thinking about the relationship 208 00:08:54,634 --> 00:08:56,892 between the electrons and the nucleus -- 209 00:08:56,892 --> 00:08:58,846 is that you can imagine the electrons 210 00:08:58,846 --> 00:09:00,835 are kind of moving around, 211 00:09:00,835 --> 00:09:02,956 buzzing around this nucleus. 212 00:09:02,956 --> 00:09:04,692 One model is you could kind of 213 00:09:04,692 --> 00:09:06,700 thinking of them as orbiting around the nucleus, 214 00:09:06,700 --> 00:09:08,000 but that's not quite right. 215 00:09:08,000 --> 00:09:10,499 They don't orbit the way that a planet, say, 216 00:09:10,499 --> 00:09:11,660 orbits around the Sun. 217 00:09:11,660 --> 00:09:13,749 But that's a good starting point. 218 00:09:13,749 --> 00:09:16,267 Another way is that they kind of jumping around the nucleus 219 00:09:16,267 --> 00:09:18,691 or they are buzzing around the nucleus. 220 00:09:18,691 --> 00:09:19,956 And that's just because 221 00:09:19,956 --> 00:09:22,073 reality just gets very strange at this level, 222 00:09:22,073 --> 00:09:23,544 and we'll actually have to get to quantum physics 223 00:09:23,544 --> 00:09:26,408 to really understand what the electron is doing. 224 00:09:26,408 --> 00:09:29,190 But a first mental model in your head is 225 00:09:29,190 --> 00:09:32,400 at the center of this atom, of this carbon 12 atom, 226 00:09:32,400 --> 00:09:34,067 you have this nucleus. 227 00:09:34,067 --> 00:09:36,644 You have this nucleus right over there. 228 00:09:36,644 --> 00:09:40,733 And these electrons are jumping around this nucleus. 229 00:09:40,733 --> 00:09:43,009 And the reason why these electrons 230 00:09:43,009 --> 00:09:45,135 don't just go off away from this nucleus, 231 00:09:45,135 --> 00:09:47,200 why they are kind of bound to this nucleus, 232 00:09:47,200 --> 00:09:49,308 and they form part of this atom, 233 00:09:49,308 --> 00:09:54,579 is that protons have a positive charge, 234 00:09:54,579 --> 00:09:57,918 and electrons have a negative charge. 235 00:09:57,918 --> 00:10:02,477 And it's one of these properties of these fundamental particles. 236 00:10:02,477 --> 00:10:03,620 When you start thinking about 237 00:10:03,620 --> 00:10:05,467 what is a charge fundamentally other than a label, 238 00:10:05,467 --> 00:10:06,867 and it starts to get kind of deep. 239 00:10:06,867 --> 00:10:08,400 But the one thing that we know, 240 00:10:08,400 --> 00:10:10,697 when we talk about electro-magnetic force, 241 00:10:10,697 --> 00:10:13,146 is that unlike charges attract each other. 242 00:10:13,146 --> 00:10:14,959 So the best way to think about it is: 243 00:10:14,959 --> 00:10:16,546 protons and electrons, 244 00:10:16,546 --> 00:10:18,133 because they have different charges, 245 00:10:18,133 --> 00:10:20,129 they attract each other. 246 00:10:20,129 --> 00:10:21,457 Neutrons are neutral, 247 00:10:21,457 --> 00:10:25,088 so they're really just sitting here inside of the nucleus, 248 00:10:25,088 --> 00:10:28,579 and they do affect the properties on some level, 249 00:10:28,579 --> 00:10:33,154 for some atoms of certain elements. 250 00:10:33,154 --> 00:10:35,005 But the reason why we have the electrons 251 00:10:35,005 --> 00:10:36,818 not just flying off on their own 252 00:10:36,818 --> 00:10:38,600 is because they are attracted. 253 00:10:38,600 --> 00:10:42,333 They are attracted towards the nucleus. 254 00:10:42,333 --> 00:10:45,067 And they also have an unbelievably high velocity 255 00:10:45,067 --> 00:10:47,140 -- it's actually hard for -- 256 00:10:47,140 --> 00:10:48,446 we start touching once again 257 00:10:48,446 --> 00:10:51,546 on a very strange part of physics 258 00:10:51,546 --> 00:10:52,570 once we start talking about 259 00:10:52,570 --> 00:10:54,164 what an electron actually is doing 260 00:10:54,164 --> 00:10:55,946 -- but is has enough -- 261 00:10:55,946 --> 00:10:56,842 I guess you could say 262 00:10:56,842 --> 00:10:57,924 it's jumping around enough 263 00:10:57,924 --> 00:11:00,733 that it doesn't want to just fall into the nucleus, 264 00:11:00,733 --> 00:11:02,867 I guess is one way of thinking about it. 265 00:11:02,867 --> 00:11:08,123 And so, I mentioned carbon 12 right over here 266 00:11:08,123 --> 00:11:09,769 defined by the number or protons. 267 00:11:09,769 --> 00:11:12,403 Oxygen would be defined by having 8 protons. 268 00:11:12,403 --> 00:11:16,467 But once again, electrons can interact with other electrons. 269 00:11:16,467 --> 00:11:18,650 They can be taken away by other atoms. 270 00:11:18,650 --> 00:11:21,025 And that actually forms 271 00:11:21,025 --> 00:11:23,271 a lot of our understanding of chemistry. 272 00:11:23,271 --> 00:11:25,995 It's based on how many electrons an atom has, 273 00:11:25,995 --> 00:11:27,600 or a certain element has. 274 00:11:27,600 --> 00:11:29,467 And how those electrons are configured, 275 00:11:29,467 --> 00:11:33,867 and how the electrons of other elements are configured, 276 00:11:33,867 --> 00:11:36,018 or maybe other atoms of that same element. 277 00:11:36,018 --> 00:11:41,267 We can start to predict how an atom of one element 278 00:11:41,267 --> 00:11:43,333 can react with another atom of that same element, 279 00:11:43,333 --> 00:11:46,733 or an atom of one element -- how it could react, 280 00:11:46,733 --> 00:11:49,695 or how it could bond, or not bond, or be attracted to, 281 00:11:49,695 --> 00:11:52,200 or repel another atom of another element. 282 00:11:52,200 --> 00:11:53,420 So for example, 283 00:11:53,420 --> 00:11:56,300 and we'll learn a lot more about this in the future, 284 00:11:56,300 --> 00:12:00,144 is: it is possible for another atom some place 285 00:12:00,144 --> 00:12:02,723 to swipe away an electron from a carbon, 286 00:12:02,733 --> 00:12:05,552 just because for whatever reason -- 287 00:12:05,552 --> 00:12:10,338 and we'll talk about certain neutral atoms of certain elements 288 00:12:10,338 --> 00:12:13,723 have a larger affinity for electrons than others. 289 00:12:13,723 --> 00:12:15,218 So one, maybe one of those, 290 00:12:15,218 --> 00:12:17,160 swipes an electron away from a carbon, 291 00:12:17,160 --> 00:12:19,230 and then this carbon will be 292 00:12:19,230 --> 00:12:21,831 having less electrons than protons, 293 00:12:21,831 --> 00:12:25,138 so then we'll have 5 electrons and 6 protons. 294 00:12:25,138 --> 00:12:27,800 And then we'd have a net positive charge. 295 00:12:27,800 --> 00:12:30,039 So in this carbon 12, the first version I did, 296 00:12:30,039 --> 00:12:34,267 I had 6 protons, 6 electrons, the charges canceled out. 297 00:12:34,267 --> 00:12:36,553 If I lose an electron, then I only have 5 of these, 298 00:12:36,553 --> 00:12:38,933 and then I would have a net positive charge. 299 00:12:38,933 --> 00:12:40,785 And we're going to talk a lot more 300 00:12:40,785 --> 00:12:42,867 about all of this throughout the chemistry playlist, 301 00:12:42,867 --> 00:12:44,302 but hopefully you have an appreciation that 302 00:12:44,302 --> 00:12:46,133 this is already starting to get really cool. 303 00:12:46,133 --> 00:12:51,800 We can already get to this fundamental building block 304 00:12:51,800 --> 00:12:53,118 called the atom. 305 00:12:53,118 --> 00:12:54,920 And what's even neater is that 306 00:12:54,920 --> 00:12:56,759 this fundamental building block is built of 307 00:12:56,759 --> 00:12:58,667 even more fundamental building blocks. 308 00:12:58,667 --> 00:13:00,867 And these things can all be swapped around 309 00:13:00,867 --> 00:13:03,129 to change the properties of an atom, 310 00:13:03,129 --> 00:13:06,044 or even go from an atom of one element 311 00:13:06,044 --> 00:13:09,036 to an atom of another element.