The number of ........ in an atom dictates which element the atom is.

• electrons

• protons

• neutrons

• atomic mass

Protons and neutrons are collectively called

Isotopes are elements with same number of protons but different number of

Isotopes have different chemical properties

• true

• false

The element chlorine has two isotopes, chlorine-35 and chlorine-37. The abundance of these isotopes when they occur naturally is 75% chlorine-35 and 25% chlorine-37

Calculate the average relative atomic mass for chlorine

Atom A has 5 protons and 5 neutrons. Atom B has 6 protons and 5 neutrons. These atoms are:

• allotropes

• isotopes

• isomers

• atoms of different elements

If a sample contains 19, 9% boron-10 and 80, 1% boron-11, calculate the relative atomic mass of an atom of boron in that sample.

correct to one decimal place

Considering the atom model who discovered the nucleus

• Thomson

• Rutherford

• Dalton

• Bohr