Atomic Structure

​Grade 7
Grace

Multiple Choice

Atom consists of...

• Electron, proton, neutron

• Electron, positron, neutron

• Electron, proton, nuckleus

• Only Electron

Multiple Choice

The core of the atom consist of ..

• proton and electron

• proton and neutron

• electron and neutron

• only proton

Describing Nucleus

• Atom = nucleus (proton and neutron) and electrons

• Nucleus = protons and neutrons at the centre of the atom

​Proton Number (Z)

• The number of protons in an atom is called its proton number (it can also be called the atomic number)

Nucleon Number (Z)

• The total number of particles in the nucleus of an atom is called its nucleon number (or mass number)

• The mass number is the number of protons and neutrons in the atom

• The number of neutrons can be found by subtracting the atomic number from the mass number

​Number of Neutrons = Nucleon Number - Proton Number

Example

​Practice