Grade 9 · Science · Unit 6 of 11
The Periodic Table
Groups, periods and patterns
What your child practises
Groups and periods, metals, non-metals and metalloids, alkali metals, halogens and noble gases, and how valence electrons and shells explain the patterns.
Ontario Curriculum expectation: C2.4, C2.5 · how an element's position in the periodic table relates to its atoms and properties
Sample questions
A taste of this unit. In the app, questions change every time and get easier or harder to match your child.
Question 1
The elements in a period all have the same number of…
- neutrons
- valence electrons
- electron shells
- protons
Show answer
electron shells
Hint: Going across a period, the outer shell fills up but the shell count stays the same.
Question 2
Argon has electrons arranged 2, 8, 8. Which period (row) is it in?
answer box
Show answer
3
Hint: The number of occupied shells is the period number: 3.
Question 3
Which element has 3 electron shells and 1 valence electron?
- Sodium
- Carbon
- Boron
- Beryllium
Show answer
Sodium
Hint: 3 shells puts it in period 3, and 1 valence electron places it in group 1: that is sodium.
Question 4
Chlorine has electrons arranged 2, 8, 7. Which group (column) number is it in?
answer box
Show answer
17
Hint: The outer shell has 7 valence electrons. For this element that means Group 17 (groups 13 to 18 have 3 to 8 valence electrons).
Question 5
Which pair is likely to have the most similar chemical properties?
- sodium and chlorine
- oxygen and magnesium
- carbon and neon
- sodium and potassium
Show answer
sodium and potassium
Hint: Both are in Group 1.
Question 6
A solid is dull, brittle and does not conduct electricity. It is most likely a…
- transition metal
- alkali metal
- metal
- non-metal
Show answer
non-metal
Hint: Sulphur and carbon (as coal) are examples of non-metals.