ATOMIC STRUCTURE OF A CARBON ATOM

BY KATHERINE WHITNEY

INFORMATION ON THE STRUCTURE OF AN ATOM.

AN ATOM HAS TWO SECTIONS:

NUCLEUS

• In the nucleus are the atomic sub-particles – protons and neutrons.

ELECTRON CLOUD

• In the electron cloud are the electrons.

ATOMIC SUB-PARTICLES

PROTONS (+)

Are positively charged

Have a mass of 1 AMU each

Found in the nucleus

NEUTRONS (0)Have no charge – they are neutral

Have a mass of 1 AMU each

Found in the nucleus

ELECTRONS (-)Are negatively charged

Have very little mass (so we just say 0 for the mass when working with the structure of an atom)

Found in the electron cloud

HOW TO FIND THE NUMBER OF PROTONS, NEUTRONS AND ELECTRONS IN AN ATOM.• To find the number of protons (+) look at the elements atomic

number. This number is the number of protons and in a neutral (or stable) atom it is a guide to the number of electrons (electrons have to be the same number as protons in a neutral atom).

• To find the number of electrons you can use two methods. The easiest one is to subtract the atomic number from the atomic mass but sometimes the students cannot recognize that this is occurring. In this case just use a simple first grade math problem: AM = P + N. Insert the numbers known; atomic mass and protons and solve for the neutrons. (Ex. Carbon: 12 = 6 + ___ )

ELECTRON CONFIGURATION IN THE ELECTRON CLOUD

To arrange electrons you have to follow the 2, 8, 8 rule. This is easy for the first couple periods on the periodic table so if you are dealing with young students then I suggest you don’t go past number 18 on the periodic table.

The first energy level outside the nucleus can hold up to 2 electrons. If you have more than two you go to the next energy level which can hold up to 8 and if you have more than 10 electrons then proceed to the next energy level which can hold 8 as well. It gets more complicated after 18 electrons.

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EXAMPLE – A CARBON ATOMThe atomic number is 6 so there are 6 protons and because there are 6 protons the neutral atom has to have 6 electrons to balance the positives with the negatives.

The atomic mass is 12 so we can subtract the atomic number (6) from the atomic mass and get the number of neutrons which is 6.

Protons = 6

Neutrons = 6

Electrons = 6

EXAMPLE: A CARBON ATOM

Nucleus

Protons 6Neutrons 6

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Follow up with the program (Atomic Structure) set up in SNAP!The End