Atomic Structure: Protons, Electrons & Neutrons

in the previous video we discovered that all the atoms in the periodic table are made from just three kinds of particles protons electrons and neutrons the whole world in fact amazing we know that the heavy protons and neutrons live in the atoms center called the nucleus the proton carries a positive electric charge and the neutron is neutral the light electrons whizzed around the outside of the nucleus and trace out the shape of a fuzzy ball they carry a negative electric charge we can show the electrons moving but it will be easier to keep them still in this video we can still learn important things about atoms by simplifying the real picture let's pretend we have a pile of each of these particles and then build some atoms from scratch what's the simplest and lightest atomy can think of it must be the one with an atomic number of one did I hear you say hydrogen it makes sense that this atom is made by using just one proton how many electrons does a hydrogen atom need have you noticed that stuff around us is not electrically charged most of the time you don't go around with your hair standing on end from static electricity that means that atoms are overall neutral so that the positive charge of the proton must be exactly canceled by the negative charge of an electron and just one electron the number of protons and electrons must be the same a hydrogen atom has one proton and one electron the number of protons equals the number of electrons and this is true for all atoms what's the next atom on the periodic table helium to make a helium atom requires 2 protons and how many electrons 2 we've just learned that two pluses and two minuses overall neutral but we have a problem piston the two protons in the nucleus both carry the same charge why is this a problem they will repel each other so the nucleus will fly apart this is where neutrons come in handy neutrons provide some extra glue to hold the nucleus together there's an extra attractive force that belongs in the nucleus called the strong nuclear force that works only between nuclear particles without this force the nucleus would disintegrate who again by the way if they won't tell you about the strong nuclear force until you get to university so this is a kind of trailer for you a hydrogen atom doesn't need a neutron why it has only one proton in its nucleus so it won't feel any repulsive forces by nearby protons hydrogen is the only atom that can do this all other atoms must have neutrons in their nucleus to keep it together but from now on we're going to ignore the neutrons in building our atoms to make our video easier to follow let's remember though that neutrons are found in all atoms that have more than one proton how do we make the third atom lithium power bet with three protons and three electrons that's correct but we've got another problem Houston electrons live in shells that are wrapped around the nucleus and the first shell can take only two electrons before it becomes full so lithium has too many electrons to squeeze them all into the first shell luckily there are plenty of shells available so after two electrons filled the first shell the extra electron can go into the next shell this second shell is bigger than the first shell and can take up to eight electrons this is like a strange hotel that has only two beds on its first floor so after two guests are booked in extra guests have to be sent to the higher floor the hotel second floor has fake beds and so after the next eight guests booked in this floor is also full a lithium atom has three protons in its nucleus two electrons in its first shell and one electron in its second shell the number of electrons in each shell is incredibly important because it affects the properties of the element and how it will behave in the world for example lithium is a metal because it has a single electron in its outer shell we will explain how this happens later the number of electrons in each shell of an atom is called its electron configuration you should ask your parents if they know what electron configuration means they're really cool words to learn the electron configuration of lithium is two electrons in the first shell and one electron in the second shell or sometimes scientists just write two comma one for short we're on a roll here what is atom number four and how many protons and electrons does it have and where do they live did you say beryllium with four protons and four electrons with all four protons living in its nucleus two electrons in its first shell and two in its second shell if so you can move to grade 11 in high school beryllium electron configuration is 2 comma 2 2 electrons in the first shell and 2 electrons in the second shell next Adam is number five boron it has five protons and five electrons two electrons in its first shell and three electrons in its second shell its electron configuration is 2 comma 3 number six carbon six protons and six electrons its electron configuration is two four do you notice a pattern here the number of the atom it's atomic number is always the same as the number of protons in its nucleus earlier we learned that atomic number meant the place of an atom in the list of atoms from the lightest to the heaviest when scientists discovered these subatomic particles they realized that atomic number was also exactly equal to the number of protons in the nucleus it means that an atom's identity that is whether it is hydrogen or aluminium or gold depends only on how many protons are in its nucleus the atomic number of an atom is equal to the number of protons in its nucleus we could have defined the atomic number as the number of electrons as this is the same as the number of protons in an atom however electrons can sometimes be swiped off the outside shell of an atom or an atom may grab an extra electron or two so this number of electrons can vary from time to time protons live in the nucleus which is locked away from the outside world and their numbers don't vary usually this is a better definition let's use up the rest of our protons and electrons number seven nitrogen seven protons and seven electrons electron configuration two five two electrons in the first shell and five in the second shell number eight oxygen eight protons and eight electrons electron configuration two six two electrons in the first shell and six in the second shell 9 fluorine nine protons and nine electrons electron configuration - seven electrons in the first shell and seven in the second shell number 10 nyan 10 protons and 10 electrons Tron configuration 2 8 two electrons in the first shell and eight in the second shell remember how many electrons that the second shell can take before it's full eight this means that neon second shell is full this has important consequences for neon and at an unreactive noble gas we will explain why this happens later can you guess what might happen if we had another proton and electron we would the electron go what is this we've just built atoms of the first ten elements on the periodic table each one has a different number of protons and electrons and a different electron configuration too as you learn more about atoms you will discover that these elements are what they are because of these protons and electrons and how they will put together for example hydrogen is an explosive gas because it has just one electron in its outer shell and helium is an unexploited gas because it has two electrons in its outer shell and lithium is a shiny metal because it has an electron configuration of two one we will explain how this works later our world is as it is because of these little subatomic particles and how they are arranged that is because of atomic structure

Channel: AtomicSchool

Views: 1,685,198

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Keywords: Chemistry, atomic structure, atoms, protons, electrons, neutrons, chemistry tutorial, tutorial video, online chemistry course, chemistry course, chemical, primary school, science students, atomic school, Ian stuart, science videos, chemistry class, high school, scientists, scientific concepts, Australian schools, World Science Festival, genetics, electronics, nanotechnology, engineering, astronomy, biology, physics, Iran, India, Philippines

Id: EMDrb2LqL7E

Length: 13min 31sec (811 seconds)

Published: Tue May 13 2014