Periodic Table & Trends

Why do the elements in the same group behave similarly?

• They have the same number of protons

• They have the same number of outer electrons (valence electrons)

• They have the same number of neutrons

• They have the same number of shells

As you go down group 2, how many electrons will the elements have in the outer shell?

• 1

• 2

• 3

• 4

What happens to the size of the atom (atomic radius), as we go down the group?

• Increases

• Decreases

• Stays the same

Why does this trend in atomic radius size occur as we go down the group?

• There is an extra shell for each element as we go down the group

• There is one shell less for each element as we go down the group

• The shell number stays the same as we go down the group

What happens to the size of the atomic radius as we go across the period?

• Increases

• Decreases

• Stays the same

Why do we see this trend in atomic radius as we go across the period?

• The number of protons increases as we go across the period and so the attraction between the nucleus and the outer electron increases and pulls the electron towards the nucleus, therefore the atomic radius gets smaller

• The number of protons decreases as we go across the period and so the attraction between the nucleus and the outer electron lessens and the electron is not pulled towards the nucleus, therefore the atomic radius gets bigger

• Nothing happens

If we add an electron to an atom (so making it a negative ion) what happens to the ionic radius and why?

• The electrons repel each other so the radius gets bigger

• The electrons increase so it gets bigger

• Nothing changes

What is ionisation energy?

• The energy needed to remove a proton from the atom

• The energy needed to remove a neutron from the atom

• The energy needed to remove an electron from the atom

Is it easier to remove an electron that is ...

• Closer to the nucleus

• Further away from the nucleus

• On it's own and unpaired

As we go across the period, we see the atomic radius decreases in size due to increasing protons. So, what happens ionisation energy as we go across the period?

• Decreases

• Increases

• Stays the same