GCSE - General Certificate of Secondary Education Atomic Structure & Periodic Table Questions and Answers

Question 1

An atom has an atomic number of 11 and a mass number of 23. How many protons, neutrons, and electrons are in this atom?

Accepted Answer

11 protons, 12 neutrons, 11 electrons

Answer

The atomic number represents the number of protons. In a neutral atom, the number of electrons is equal to the number of protons. The mass number is the sum of protons and neutrons, so to find the number of neutrons, you subtract the atomic number from the mass number (23 - 11 = 12).

Question 2

Which of the following statements correctly describes isotopes?

Accepted Answer

Atoms of the same element with the same number of protons but a different number of neutrons.

Answer

Isotopes are defined as atoms of the same element that have the same number of protons (and thus the same atomic number) but different numbers of neutrons. This results in them having different mass numbers.

Question 3

An element is located in Group 17 (or Group 7) of the periodic table. Which of the following properties is it most likely to have?

Accepted Answer

It has 7 electrons in its outer shell and is a reactive non-metal.

Answer

Elements in Group 17 are the halogens. They are characterized by having 7 electrons in their outer shell. This makes them highly reactive non-metals, as they tend to gain one electron to achieve a stable, full outer shell.

Question 4

A scientist discovers a new element with the electron configuration 2, 8, 5. In which period and group of the periodic table would this element be placed?

Accepted Answer

Period 3, Group 5 (or 15)

Answer

The number of electron shells (in this case, three: 2, 8, 5) determines the period number, so it is in Period 3. The number of electrons in the outermost shell (5) determines the group number for main group elements, placing it in Group 15 (or 5).

Question 5

Which statement best describes the development of the modern periodic table?

Accepted Answer

Henry Moseley's work on atomic numbers led to the elements being arranged in order of increasing atomic number, resolving inconsistencies in Mendeleev's table.

Answer

While Mendeleev did amazing work by arranging elements by atomic mass and leaving gaps for undiscovered elements, his table had some inconsistencies. Henry Moseley later discovered that arranging elements by their atomic number (the number of protons) created a more accurate and consistent periodic table.

GCSE - General Certificate of Secondary Education Practice Test

GCSE - General Certificate of Secondary Education Practice Test

GCSE - General Certificate of Secondary Education Atomic Structure & Periodic Table Questions and Answers