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Leaving Cert Chemistry: The periodic table

How often The periodic table comes up on the Chemistry papers, every year it was asked, and questions to try.

HL Asked on 5 of the last 10 Higher Level papers, most recently in 2025.

OL Asked on 10 of the last 10 Ordinary Level papers, most recently in 2026. banker

June 2027 is the first exam on the new Chemistry course. These come from the 2016–2026 papers, so read them as a guide.

The periodic table, Higher Level(6 marks)

Quick ones on The periodic table.

(a)Group 1 elements are known as the?
  1. Alkaline earth metals
  2. Alkali metals
  3. Halogens
(b)Elements in the same group of the periodic table have the same?
  1. Relative atomic mass
  2. Number of neutrons
  3. Number of outer electrons
(c)Who arranged the elements by atomic mass and left gaps for undiscovered elements?
  1. Mendeleev
  2. Dobereiner
  3. Newlands
Show the answers

(a) Alkali metals

(b) Number of outer electrons

(c) Mendeleev

Your turn: Higher Level questions on The periodic table.

Higher Level

Asked on 5 of the last 10 Higher Level papers, most recently in 2025.

Every paper, year by year

YearWhere it came up
2026Not asked
2025Q4(a)
2024Not asked
2023Not asked
2022Q4(a)
2021Q5
2019Q5
2018Not asked
2017Q4(a)
2016Not asked

Links open the State Examinations Commission’s paper for that year.

More The periodic table questions

The periodic table, 2 marks

Which element is in period 4 and group 2?

  1. Magnesium
  2. Potassium
  3. Calcium
Show the answer

Calcium

Period 4 means four occupied main levels and group 2 means two outer electrons: 2, 8, 8, 2 is calcium.

Ordinary Level

Asked on 10 of the last 10 Ordinary Level papers, most recently in 2026. banker

Every paper, year by year

YearWhere it came up
2026Q4(k)
2025Q11(a)
2024Q11(a)
2023Q5
2022Q4(a)
2021Q11(a)
2019Q11(b)
2018Q4(a)
2017Q5
2016Q5, Q7

Links open the State Examinations Commission’s paper for that year.

More The periodic table questions

The periodic table, 2 marks

Halogen that is a yellow-green gas at room temperature?

  1. Bromine
  2. Iodine
  3. Chlorine
Show the answer

Chlorine

Bromine is a red-brown liquid and iodine is a dark grey solid at room temperature.

The periodic table, 2 marks

Group 2 elements are known as the?

  1. Alkali metals
  2. Alkaline earth metals
  3. Transition metals
Show the answer

Alkaline earth metals

Group 2 includes magnesium and calcium. They have two outer electrons and form 2+ ions.

The periodic table, 2 marks

The modern periodic table is arranged in order of increasing?

  1. Atomic number
  2. Atomic mass
  3. Number of neutrons
Show the answer

Atomic number

Moseley showed that atomic number, not mass, is the right order. This fixed pairs such as argon and potassium.

Other Chemistry topics

All of Leaving Cert Chemistry