00:00 Hello everyone, my name is Akeredolu O.O. Mrs. I am your chemistry teacher and a lesson

00:20 for today is "particulate nature of matter at one." At the end of the lesson, the students

00:32 should be able to distinguish between chemical and physical change with examples, distinguish

00:40 between atoms and molecules, describe subatomic particles and their arrangement in the atom,

00:49 define atomic number, mass number, and also state that is atomic theory.

00:58 "Mata" Science interprets nature in terms of energy and matter.

01:06 Matter, the material of which the universe is composed may be defined as anything that

01:14 has mass and occupy space. "Mata" exists in three physical states, the geysers states, the

01:24 liquid states, and the solid states. Examples of matter. In geysers states, we have examples

01:34 like oxygen, vapor, air. Examples of liquid matter. We have water, kerosene, palm oil. An

01:46 example for solid state of matter, we have stone, common salt, and iron road.

01:55 Physical properties of matter, types of properties of matter include physical properties and chemical

02:04 properties. Physical properties. There are properties associated, these are properties

02:11 associated with physical changes, occurring in a matter. They include boiling points, melting

02:20 points, density, hardness, malleability, solubility, color, crystalline form, taste, and odor.

02:33 We see that physical states is more of what you can use the five senses to see.

02:44 Physical properties of matter include involve substance when a substance undergoes a change

02:52 of form when a new substance is formed. These include all chemical reactions with water,

03:02 with acids, with basis, and other reagents. And when substances are exposed to air, we can

03:09 equally have chemical changes. We are new substances are formed. Roasting of iron is also a chemical

03:17 property of iron. Since a new substance, iron, iron loss, iron loss is a new substance entirely.

03:26 Quite different from iron, is food. Types of changes. There are two types of changes. We have

03:36 the physical change and chemical change. If physical change is easily reversible, thus does

03:44 not form new substance and usually does not involve a great heat change. On the other hand,

03:52 a chemical change is not generally reversible. It forms new substances and may involve great

04:00 heat change. Examples of physical and chemical changes are given. Physical changes we have

04:10 examples like the solution of common salt in water. When you pour your salt in water, it dissolves.

04:18 It looks like you are not seeing the salt again. But it's a physical change because that salt

04:26 can be gotten back. If you remember our lesson on separation of mixture, it's just a mixture.

04:32 It can be gotten back. No new substance formed. That is a physical change. Another one is melting of

04:39 ice. If you have ice block, it can melt and you have liquid water. It is still water. No new

04:48 substance is formed too. That's another physical change. It can't do wax. When can't do melt?

04:54 You see that it's going to liquid form. Just another state of matter. No new substance is formed.

05:00 It can solidify back to your kind. No new substance is formed. That's a physical change.

05:06 Also, freezing of liquid to solid. If you put water inside the freezer, it becomes solid. There is

05:14 no chemical change from that. It's just physical change because you can still get your water back.

05:20 Vaporization of liquid. When you heat water, it changes. You see it changed to ratios 4. That's

05:27 another physical change. Liquidification of gases. Sublimation of harmful, naphthalene, iodine,

05:36 ammonium chloride. We saw these as examples of substances that can subline. Change directly from

05:42 solid to geostate. You can still get your substances back. So that's a physical change.

05:48 Magnetization of iron. When you hold a magnet surrounding an iron, it moves on. You can still get

05:56 your iron back. That's a physical change. Examples of chemical change. We have burning of wood

06:05 or paper. When you burn wood or paper, you cannot get the paper back. A new substance is formed

06:12 called ashes. That's a new compound. A different substance entirely. That is a physical change.

06:18 The solution of metal or limestone in acid. A new compound is formed. The solution of sodium or

06:26 calcium in water. A new substance is formed. Lost scene of iron is another chemical change. Because

06:32 that iron lost is a new compound. Burning of magnesium limping in air. A new substance is formed.

06:40 Electrolysis of a compound, fermentation, and decay of substances. When you keep your

06:47 palm on a palm, that's your wine. You tap your palm wine and you put it for a while. When it

06:57 fragments, once you have, it's no longer your palm wine. You have in alcohol and some other things.

07:02 That is a chemical change. Because yeast has a reactant. A lot of chemical change has happened.

07:08 A new substance is formed. Sleeking of lime. And the digestion that takes place in our body

07:16 is a chemical change. When you put in your lamp, what comes out of it? A new taste that I useful

07:22 for the body. And carbon dioxide that you breathe out. That's a new substance is formed.

07:27 That's another chemical change. Now, we have seen a matter. It could be in the solid state. It could be

07:37 in the liquid state. It could also be in the gaseous form. But every matter,

07:44 whether an element or whatever, are basically formed by atoms. Atoms are the basic building block

07:57 of matter. An atom is defined as the smallest particle of an element. That returns its chemical

08:04 identity of that element. You can also define an atom as the smallest particle of an element,

08:15 which can take part in chemical reaction. That is, the identity of that element is still intact.

08:27 Molecule. A molecule is the smallest particle of a substance. It could be an element

08:36 or a compound that can exist on its own and still retain its properties of that substance.

08:45 A molecule can be a consist of the atoms of the same element or atoms of different elements.

08:54 For example, let's look at oxygen. Oxygen, this is an element of oxygen, this is an atom of oxygen.

09:05 An atom of oxygen. But you can have a molecule of oxygen. A molecule of oxygen that can exist on its own

09:17 requires two atoms. So, this is a molecule of oxygen. An atom is the smallest particle of that element.

09:31 That returns the chemical reaction. And a molecule is a substance that can stay on its own.

09:36 I said it could be an element and it could be different elements that form a compound.

09:42 For example, you can have a molecule of HCl, hydrogen, bonding with chlorine.

09:50 This is one molecule of HCl. You can equally have water where you need two atoms of oxygen,

09:58 bonding with oxygen. This is one molecule of oxygen. The number of atoms in a molecule of an

10:08 element is called atomicity.

10:11 Elements may be monatomic. That is, just one atom of it can stand on its own.

10:25 And those ones are said to be monatomic.

10:37 Can be monatomic, that is, having one atom in one molecule of it. They are said to be monatomic.

10:47 Monatomic.

10:57 For example, helium element, helium one atom of helium can stand on its own as its molecule.

11:07 It's said to be monatomic. I mean one atom in one molecule. The atomicity of such element is said to be one.

11:16 Then we can have the atomic molecules.

11:24 That is, for that substance to stay low, it needs two atoms of it. For example, oxygen.

11:34 This is one molecule of oxygen with two atoms of it. Chlorine is another example.

11:44 Having two atoms of it, a one molecule. So the atomicity of oxygen or chlorine,

11:51 any element that's in that atomic is two. We can also have tratomic molecules.

11:58 This one's contains three atoms in one molecule as you find in Ozo tratomic.

12:08 Ozo has one molecule of it as three atoms. And we have polyatomic molecules.

12:21 Which contain more than three. Like phosphorus, like sulfur. One molecule of it will contain more than three.

12:32 Now, at the beginning of the lesson, we learned that scientists

12:41 propound theories or principles. That is, a scientist propounded the theory about the atom,

12:52 the smallest atom of an element. And this is the theory. The atomic theory of matter states

13:00 matter is made up of tiny particles called atom. The scientist that propounded this theory

13:08 is called Dalton. Dalton propounded a theory about the atom.

13:19 And there are so many of it. Talking about what an atom is.

13:25 Dalton atomic theory is summarized. It said all elements are made up of small

13:37 indivisible particles called atoms. That was its work. And every element,

13:43 their building block is an atom and it is indivisible.

13:48 Dalton also propounded another and another thing about atomic theory.

13:53 That atoms can neither be created nor destroyed. He also says atoms of the same element are exactly

14:02 alike in every aspect and different from an atom of another element. That is,

14:09 if you take element oxygen, all is atom. Everything they are alike. It will be different from that of

14:16 chlorine. All the atoms of chlorine are also alike. Atoms of the same element are exactly alike

14:25 in every aspect. Also it says when atoms combine with other atoms, they do so in simple ratios.

14:34 Another theory Dalton propounded was that atoms of the same element are exactly alike in every

14:42 aspect and differ from atoms of other elements. In other words, if you take element oxygen,

14:49 all the atoms of oxygen are alike, but differ from atoms of chlorine.

14:55 When atoms combine with other atoms, they do so in simple ratios, meaning that

15:04 what we found in formation of water, this is in ratio of ratio 2 to 1.

15:12 So Dalton says when every compound is formed, they do so in simple ratios.

15:17 Also Dalton propounded that all chemical changes resolve from the combination of separation of atoms.

15:32 Now, science is not static. It is dynamic. Walks keep going on. So many researches.

15:41 And then it was discovered that Dalton atomic theory needs to be modified.

15:48 Dalton said atoms are composed of small, indivisible particles of an element, but it was discovered

16:00 that an atom has particles, an atom has a nucleus and there are some negative particles that are found

16:13 outside the nucleus. And in the nucleus, there are two particles. We have the neutron

16:22 and the proton. Also outside the nucleus, there are negative particles called electrodes found.

16:32 So we cannot say that atoms is indivisible, so that is a modification. Atoms are composed of small

16:40 particles called protons, neutrons and electrons, which are found in an atom. So they are not

16:47 indivisible. Actually, there are particles in atoms. Also, new atoms may be created because

16:55 Dalton said atoms can neither be created nor destroyed. But in the chemistry, in nuclear chemistry,

17:01 nuclear fission and fusion, nuclear fission and fusion, we discovered that nucleus of atoms

17:16 can be fixed together to form new ones and everyone can be broken down and new atoms are formed.

17:24 So another modification to Dalton's atomic theory is that atoms of the same

17:30 element are not exactly alike in every way because of the phenomenon called isotropy.

17:40 Who gets to that? Also, giant organic molecules and complex compounds are not usually formed by

17:50 simple ratios. When we say giant molecules, you can know that the ratios are not simple at all.

18:01 Then the atomic structure. Atoms can be split into smaller particles called protons, neutrons

18:15 and electrons. Now, atoms ask the nucleus, which I said has two particles. We have the protons

18:35 and the neutron that these two forms the nucleus. And outside the nucleus, there are some negative

18:51 particles called the electrons. This is the structure of an atom. An atom asks a nucleus which

19:01 has two particles, the proton and the neutron. Now, these electrons are found in places called the shell.

19:09 The shell closes to the nucleus. It's called the K shell. And we have

19:26 depending on the element. Depending on the element, you can have several shells.

19:34 And in all these shells, those are the places whereby you can find

19:47 electrons located. The mass of an atom is concentrated in the nucleus.

20:02 Atomic mass is gotten from the nucleus. So, then electron does not contribute to the mass of the

20:13 atom because the electrons are found outside the nucleus of the atom. Note that it is the nucleus

20:21 that compose of form the mass of that atom. Atoms are electrically neutral because they contain

20:31 equal number of protons and neutrons. Why? I said we have electrons. Three particles now

20:42 in an atom. The neutron has a neutron charge that is no charge is neutron. The electrons

20:57 are negatively charged. While the protons are positively charged.

21:10 So, if I have the same amount of proton in an atom, we have proton equal the neutron.

21:26 So, if I have plus two and the other one, that's proton. The electron, sorry. Number of protons

21:38 is the same as number of electrons. Number of protons is the same as number of electrons.

21:48 Let's remember that proton is positively charged. Electron is negatively charged. So, if they are

21:54 the same. It means I have plus two minus two. Remember that neutron is neutral. So, an atom is

22:04 electrically neutral. No charges. Atomic particles, as we have seen, protons, neutrons, electrons.

22:13 They have some properties. Let's look at their masses. Protons as one unit, it is positively charged

22:22 as I've said. And the location where you find the proton is in the nucleus of the atom.

22:27 Neutron also has one unit mass. It is neutral. It is also located in the nucleus.

22:36 While electron has one all over 1840 units, it is negatively charged. And it is found in the shelves.

22:50 Now, the number of electrons found outside the nucleus are arranged. Arrangement of this

23:01 electron is what is called electronic configuration. Now, we arrange electrons in the shelves.

23:10 The proton and neutrons are packed in the nucleus of the atom. The electron move around the nucleus

23:18 in a distinct energy level, or shelves, or orbits, according to both. The electronic

23:25 configuration is governed by the duplet and octet room. Now, what do I mean by duplet and octet room?

23:34 The atom, the shelves, closest to the nucleus, will contain a maximum of two electrons.

23:54 Two electrons. And these two electrons are located on the shelf. This shelf, like I told you before,

24:09 is the K shelf. Also, depending on the number of electrons in the element, depending on the

24:21 element, that tells us the number of electrons. Now, if you have more than two electrons,

24:28 it goes to the next shelf, which is the L shelf? If you have more electrons, it goes to the next shelf,

24:41 which is the M shelf. And more electrons, it goes to the next shelf, which is the N shelf.

24:51 Now, it is either the electrons, if you have two, the K shelf will take a maximum of two electrons.

25:01 All of that shelf will take a maximum of eight electrons. So, when it has two, that is the duplet,

25:13 and when it has eight, that is the octet. Duplet rule and octet rule. For example, in helium,

25:24 helium has two electrons. And the two electrons are found in the first shelf, the closest shelf

25:34 to the nucleus, which is the K shelf having two electrons. Now, neon, another element, has ten

25:44 electrons. And you see two in the innermost shelf and eighth, which is the maximum that the K shelf

25:54 can take. So, let's quickly, let's quickly look at some other element like oxygen,

26:08 like oxygen. Oxygen as atomic number eight, that is, it has eight electrons. And if I most

26:19 put it into electronic configuration, if I should put it inside the shelf, it takes the innermost

26:28 shelf first, it takes a maximum of two, if two is off, what I have remaining is six. So, the six,

26:36 remaining electron goes to the next shelf, which is the L shelf, and it stays there, six.

26:42 It has not exited the maximum. So, the six will stay there. So, if I have like sodium,

26:50 sodium as atomic number 11. So, if I want to arrange it into electronic configuration,

27:00 let's remember K shelf first, having the maximum of two. So, two, then we have, how many remaining?

27:10 We have nine remaining. So, the next shelf will take a maximum of eight. So, the eight stays there.

27:18 We are left with one electron. We go to the next shelf and it stays there. That is how

27:25 electrons are arranged into the atom, which we call electronic configuration.

27:32 The atomic shelf is from the inner shelf out to using alphabet K, L, M, M, O, P, Q, shelf.

27:42 The K shelf carries the maximum of two electrons. L and the others, shelves carry a maximum of eight

27:49 electrons. The maximum number of electrons for a giving shelf is two M squared.

27:56 So, electronic configuration of the first twenty elements. We have hydrogen with atomic number one.

28:06 That is, it has one electron. So, we just put the one. Helium two. Now, as you see,

28:16 the number of electrons is determined, what will write in the electronic configuration.

28:21 Making sure that you start with the K shelf first and whatever remains of the electron goes to the

28:27 next shelf, once it reaches the maximum, it goes to the next shelf and on and on.

28:32 So, let's say aluminum there. Aluminium, as atomic number 13, it has two first,

28:42 going to the next maximum of eight, the remaining one is three. So, for our evaluation,

28:48 let's write and complete the electronic configuration of the first twenty elements.

28:55 So, evaluation, evaluating what we have done, lists the differences between physical and

29:02 chemical changes, give examples of physical and chemical changes, draw and write the structure

29:09 of the atom, state-doubtings atomic theory. Thanks for watching.

29:16 My name is Agrado Lu-O-O-Me-Sis. See you next time.