1. The diagram below shows two different atoms of hydrogen. 4. Which box contains only atoms?

(a) Which particle is furthest from the centre of each atom?

A. proton B. electron C. neutron D. nucleus 5. Which diagram shows the electronic configuration of a nitrogen atom?
(b) Which particle is missing from one of the diagrams?
A. electron B. proton C. neutron D. nucleus
2. The atomic structure of an unknown element is shown below.

6. The diagram shows part of the periodic table, with elements represented by
the letters M, Q, R and T.
The letters in the diagram represent elements but are not their chemical
symbols.
Use the Periodic Table to help you answer this question.

What is the atomic number and mass number for the unknown element?
Atomic Number Mass number
A 6 11
B 5 11 Which of these statements is true?
C 5 6 A. T and Q form acidic oxides B. M conducts electricity
C. M is a non-metal element D. R is a gaseous non-metal element
D 6 10
7. The following elements are found in group 0 of the periodic table.
3. The table show information about the two isotopes of boron.
Percentage isotope in He Ne Ar Kr Xe Rn
Isotope Number of protons Number of neutrons What explains their similar chemical and physical properties?
sample
1 5 5 19 A. They have the same number of valence electrons
2 5 6 81 B. They are all gases
The relative atomic mass of this sample of boron is C. They have the same number of protons and electrons
A. 10.1 B. 10.8 C. 11.5 D. 11.8 D. They have full outer shells
8. Which element, T, Q, R or M has the electronic configuration 2,8,3? 11. This question is about hydrogen (H2) and water.
(a) Hydrogen is a gas at room temperature. It exists as simple molecules.
(i) Draw a dot and cross diagram to show the arrangement of the electrons in a
hydrogen molecule.

A. Element M B. Element Q C. Element T D. Element R

9. What is the electronic configuration of silicon?

(ii) Explain why hydrogen has a very low boiling point.

…………………………………………………………………………………..
…………………………………………………………………………………..
…………………………………………………………………………………..
(b) The symbols for the three isotopes of hydrogen are
1 2 3
H H H
(i) State what is meant by the term isotopes.
…………………………………………………………………………………..
A. 2,4 B. 2,2,4 C. 2,2,8 D. 2,8,4 …………………………………………………………………………………..
10. The diagram shows the electronic configurations of six different atoms. (ii) Complete the table to show the number of protons, neutrons and electrons
in each of the three isotopes of hydrogen.
Isotope
1 2 3
H H H
number of protons
You may use the Periodic Table to help you answer this question. number of neutrons
Answer each part by writing one of the letters A, B, C, D, E or F in the box number of electrons
provided. You may use each letter once, more than once or not at all. 12. The diagram shows the electronic configuration of an atom of element X.
Give the letter that represents an atom.
(i) of a noble gas
(ii) that contains three protons
(iii) of phosphorus
(iv) of an element in Group 4 of the Periodic Table
(v) of an element in Period 3 of the Periodic Table
(vi) with a full outer shell of electrons
(a) (i) How many protons does the nucleus of the atom contain? …………….. (i) Compared to an atom of boron, an atom of aluminium has
(ii) Which group of the Periodic Table contains element X? Why? ……………………………………. protons.
………………………………………………………………………………….. (ii) Compared to an atom of boron, an atom of aluminium has
………………………………………………………………………………….. ……………………………………. neutrons.
(b) Element X has three isotopes. (iii) Compared to an atom of boron, an atom of aluminium has
The table gives the mass number of each isotope and its percentage abundance ……………………………………. electrons in its outer shell.
in a sample of element X. (c) The electronic configuration of aluminium is
Mass number Percentage abundance (%) A. 2,3 B. 2,2,3 C. 2,2,8 D. 2,8,3
14. The element carbon has three common isotopes.
24 79.0
These are carbon-12, carbon-13, carbon-14.
25 10.0
(a) Complete the table to show the number of protons and neutrons in each
26 11.0 isotope of carbon.
Calculate the relative atomic mass (Ar) of element X.
Isotope Mass number Number of protons Number of neutrons
Give your answer to one decimal place.
carbon-12 12 6 6
carbon-13 13
carbon-14 14
(b) Explain, in term of electrons, why the three isotopes have the same
13. Boron is an element in Group 3 of the Periodic Table. chemical properties.
An atom of boron can be represented as 115B …………………………………………………………………………………..
(a) Use numbers from the box to complete the sentences about this atom of …………………………………………………………………………………..
boron. (c) (i) State what is meant by the term relative atomic mass, Ar
3 5 6 11 16 …………………………………………………………………………………..
Each number may be used once, more than once or not at all. …………………………………………………………………………………..
(i) The atomic number of boron is ………………. (ii) A sample of carbon contained 98.90% carbon-12 and 1.10% carbon-13.
(ii) The mass number of boron is ………………. Use this information to calculate the relative atomic mass of carbon in the
(iii) This atom of boron contains ………………. protons. sample. Give your answer to two decimal places.
(iv) This atom of boron contains ………………. neutrons.
(v) This atom of boron contains ………………. electrons.
(b) Aluminium is another element in Group 3 of the Periodic Table.
Select a word or phrase from the box to complete each sentence about an atom
of aluminium. 15. Atoms contain three different types of particle.
fewer more the same number of These are electrons, neutrons, protons.
Each word or phrase may be used once, more than once or not at all. (a) Which one of the three particles has a negative charge? …………………...
(b) Which one of the three particles has the smallest mass? …………………...
(c) Use words from the box to complete the sentences below. (c) Different atoms of oxygen can be represented as 168O and 188O
Each word may be used once, more than once, or not at all. Select words or phrases from the box to complete the sentence about these
electrons elements molecules neutrons protons atoms of oxygen.
(i) Atoms are neutral because they contain equal numbers of atomic numbers isotopes mass numbers numbers of electrons
……………………………….. and ………………………………….
(ii) Isotopes are atoms with the same number of ………………………………. These atoms of oxygen are called …………………………………….. because
but different numbers of ………………………….. in the nucleus. their …………………………. are the same but their ………………………...
(d) An atom of magnesium can be represented by the symbol 24 are different.
12Mg
Use numbers to complete these statements about this atom. 17. Distress flares are used to attract attention in an emergency. The flares
(i) The atomic number of this atom is …………………….. contain magnesium, which burns with a bright, white flame to form
(ii) The mass number of this atom is ……………………… magnesium oxide.
(iii) The electronic configuration of this atom is ……………………… (a) The reaction between magnesium and oxygen is exothermic.
16. This question is about the elements hydrogen and oxygen. What is meant by the term exothermic?
(a) The circles in the diagrams represent molecules of hydrogen. …………………………………………………………………………………..
Which box represents hydrogen gas? (b) Which diagram shows the electronic configuration of an oxygen atom?

A B C D
(c) Magnesium ions and oxide ions are formed when magnesium reacts with
A B C
oxygen. The diagram shows the electronic configuration and charge of a
(b) The diagram below shows two different atoms of hydrogen.
magnesium ion.

(i) The particle furthest from the centre of each atom is

A. an electron B. a neutron C. a nucleus D. a proton Which diagram shows the electronic configuration and charge of an oxide ion?
(ii) The particle present in atom Y but not in atom X is
A. an electron B. a neutron C. a nucleus D. a proton
(iii) Both atoms are neutral because they have the same number of
A. electrons and neutrons B. electrons and protons
C. electrons, neutrons and protons D. neutrons and protons A B C D