ATOMIC STRUCTURE

Atomic Structure

Protons and neutrons are found in the nucleus or centre of an atom and make up most of the weight of an atom they have a similar weight to each other.

Electrons Spin

Electrons are found spinning very rapidly around the nucleus and have virtually no weight.

Moving electrons

Protons = Electrons

An atom has an overall electrical charge of 0.

Inside an atom there is the same number of protons as electrons.

E.g. sodium – 11 protons (11+), 11 electrons (11-)

E.g. carbon – 6 protons(6+), 6 electrons(6+)

Remember

Protons : positive charge ( + )

Electrons : negative charge ( - )

Neutrons : no charge.

There are approx 100 different types of atoms, each type is known as an element.

Pictures of elements of the periodic table

Each element has it’s own special atomic number

The atomic number is determined by the number of protons in the nucleus.

Eg. Sodium – 11 protons = atomic number 11 Eg. Carbon – 6 protons = atomic number 6

Each element has a different number of protons

Periodic Table

On your provided table write out the atomic numbers, names and symbols of the first 20 elements

The periodic table is on the next slide - The atomic number is in the top left corner of each square, the name is across the bottom of each square and the symbol is in the middle of each square.

Periodic Table

You are expected to learn the first 20 elements by name and symbol.

Periodic Table Song

This is a simplified version of the Periodic Table

Summary so far

Atomic Number = no. of protons

Number of protons = number of electrons

Neutral overall charge

atomic number = number of protons = number of electrons

Eg if the atomic number = 7 then number of protons = 7 and the number of electrons = 7

If the atomic number = 3 then the number of protons = 3 and the number of electrons = 3

Fill out Protons and Electrons in your table

Mass Number

Mass Number = the total weight of the atom

Mass Number = no. of protons + no. of neutrons

To calculate the Mass Number - Make a whole number from the Relative Atomic Mass found on the periodic table.

Eg RAM = 22.9 therefore mass number = 23 Eg RAM = 35.45 therefore mass number = 35

Fill out the Mass Numbers in your table

Neutrons = Mass Number – Atomic Number

To find the number of neutrons subtract the atomic number from the mass number.

Eg Mass no. = 24, Atomic no. = 12 (24 - 12 = 12) therefore number of neutrons = 12

Eg mass no. = 20, Atomic no. = 10(20 – 10 = 10) therefore number of neutrons

= 10

Fill out number of neutrons in your table

HMass number

Atomic number

Symbols can now be written like this showing more information

http://content.skwirk.com.au/content/upload/images/Secondary/NSW/Year_10/science/chemistry_a/tp1/ch2/2_1_2_Atomic_Theory.swf