Periodicity

Question 1

What do metals form?

Answer 1

• Cations in solutions/ionic compounds
• Basic oxides

Question 2

What do non-metals form?

Answer 2

• Anions in solutions/ionic compounds
• Acidic oxides

Question 3

Why do transition metals have no set valencies?

Answer 3

They have incomplete d-subshells.

Question 4

What are metalloids?

Answer 4

‘Semi-metals’ with intermediate properties between metals and non-metals.

Question 5

What is periodic law?

Answer 5

When elements are arranged in order of increasing atomic number, there is a periodic repetition of their chemical and physical properties

Question 6

Explain the trends in the periodic table in terms of atomic radius.

Answer 6

Atomic radius decreases from left to right, but increases from top to bottom. This is because moving across a period means there is an increase in electron-proton attraction, thus the electron configuration becomes more compact. Moving down a group means there is an increase in the number of electron shells, thus a larger radius.

Question 7

What is “core charge?”

Answer 7

Charge experienced by valence electrons.
Calculated by total no. of electrons - no. of inner electrons.

E.g Neon has a core charge of 8+

Question 8

What is meant by ‘electronegativity?’

Answer 8

The tendency of an atom to gain an electron. Increase from left to right, decreases from top to bottom (as there is less nuclear attraction).

Question 9

What is meant by ‘ionisation energy?’

Answer 9

The minimum energy required to remove a valence electron. Increases from left to right but decreases down a group.