Atom

Definition: Atom is the smallest unit of matter, it comes from the Greek word atomos” which means indivisible or cannot be broken down

Atom Structure

• Proton (positive charge)

• Electron (negative charge)

• Neutron (neutral)

Nucleus (Proton + Neutron)

How to Calculate

All elements are types of atoms.

The atomic number (which is normally above the letter) is the same as the number of electrons and protons

Neutrons are counted by subtracting atomic number from the atomic mass.

For example:

Carbon has the atomic number 6, thus also has 6 electrons, and 6 protons. They have an atomic mass of 12, and so the neutron is 12-6=6

Exercise

Na

Name:

Atomic Number:

Mass Number:

Electron Number:

Proton Number:

Neutron Number:

Au

Name:

Atomic Number:

Mass Number:

Electron Number:

Proton Number:

Neutron Number:

Ne

Name:

Atomic Number:

Mass Number:

Electron Number:

Proton Number:

Neutron Number:

He

Name:

Atomic Number:

Mass Number:

Electron Number:

Proton Number:

Neutron Number:

Fe

Name:

Atomic Number:

Mass Number:

Electron Number:

Proton Number:

Neutron Number: