6.4.1.2 Mass Number, Atomic Number and Isotopes

Question 1

Why is the number of protons equal to the number of electrons?

Answer 1

• atoms have no overall charge and they have equal but opposite charges

Question 2

What do all atoms of a particular element have in common?

Answer 2

• number of protons

Question 3

What is an atomic number?

Answer 3

• number of protons in an atom

Question 4

What is a mass number?

Answer 4

• total number of protons and neutrons

Question 5

What are isotopes?

Answer 5

• atoms of the same element that have different numbers of neutrons

Question 6

How can atoms turn into positive ions?

Answer 6

• if they lose one or more outer electrons