Science Year 8 - Chapter 5

An element has an atomic number of 20. This means it has:

• 20 atoms in it.

• 20 protons.

• an atomic mass of 20.

• 20 neutrons.

What is the atomic number of the atom shown in the picture?

• 13

• 14

• 1

• 27

Which statement is NOT true about atoms?

• Protons and neutrons are both found in the nucleus.

• Protons and neutrons are added together to find the atomic mass.

• Protons and electrons are both found in the nucleus.

• Atoms are identified by its number of protons.

The atomic number of Beryllium is 4. Its mass number is 9.0122. How many neutrons does an atom of Beryllium have in its nucleus?

• 4

• 4.0122

• 5.0122

• 6

The atomic number of an element is the number of _______ it has.

• protons

• neutrons

• electrons

• protons and neutrons

The mass number of an element is the amount of _________ it has.

• protons

• protons and neutrons

• electrons

• neutrons

A nucleus of an atom contains what two parts?

• Electrons and Protons

• Neutrons and Electrons

• Protons and Neutrons

How many neutrons does Chlorine (Cl) with an atomic number of 17 and an atomic mass of 35.

• 17

• 18

• 19

In the early 1900s many scientists thought that an atom consisted of a positive substance with negative charges scattered throughout the substance. Then Ernst Rutherford completed an experiment that changed our understanding of atomic structure. Now we know that an atom consists mostly of empty space with ---

• protons orbiting a dense nucleus of electron and neutrons

• electrons orbiting a dense nucleus of protons and neutrons

• neutrons and protons orbiting a cloud of electrons

• electrons and protons orbiting a cloud of neutrons

Which one describes purity or pure element?

• it has two or more different types of atom

• it has one and the same type of atoms all throughout

• it is made up of sub-atomic particles

• it is a matter and has the different subatomic particles