Atomic number, mass number and isotopes

What is present at the centre of an atom?

• The core

• The electrons

• The nucleus

Which sub-atomic particle has a mass of 1 and no charge?

• Proton

• Neutron

• Electron

What name is given to different versions of atoms that have the same number of protons but different numbers of neutrons?

• Allotropes

• Twins

• Isotopes

What is the maximum number of electrons that can fit into the second shell?

• 2

• 8

• 18

What atom has the electron configuration 2,8,5?

• Phosphorus

• Silicon

• Aluminium

Which atom is the most stable: F, Ne, Na?

• F

• Ne

• Na

Which of these elements has two electrons in its outer shell?

• Ba

• Pb

• At

Which of these elements has three occupied electron shells?

• Boron

• Silicon

• Potassium

What is the electron configuration of calcium?

• 2,8,8

• 2,8,8,1

• 2,8,8,2

What element is in Period 2, Group 7?

• Helium

• Radium

• Fluorine