WhyAtoms have a radius of about 1 x 10^-10 metres (0.1 nanometres). The nucleus is around 10000 times smaller than this.
2Multiple choice · Easy
Which two particles are found inside the nucleus of an atom?
Protons and neutrons
Protons and electrons
Neutrons and electrons
Electrons and positrons
Tap an answer to check it.
WhyThe nucleus contains protons and neutrons. Electrons orbit the nucleus in energy levels (shells).
3Multiple choice · Easy
What is the relative charge of an electron?
-1
+1
0
-2
Tap an answer to check it.
WhyAn electron carries a relative charge of -1. A proton is +1 and a neutron is 0.
4Multiple choice · Easy
Which type of nuclear radiation is the most ionising?
Alpha
Beta
Gamma
All are equally ionising
Tap an answer to check it.
WhyAlpha radiation is the most strongly ionising because alpha particles are large and highly charged, but it has the shortest range in air.
5Multiple choice · Easy
What name is given to atoms of the same element that have different numbers of neutrons?
Isotopes
Ions
Compounds
Molecules
Tap an answer to check it.
WhyIsotopes are atoms of the same element (same number of protons) but with different numbers of neutrons, giving them different mass numbers.
6Fill in the blank · Easy
When an atom gains or loses one or more electrons it becomes charged and is called an .
Answer:
ion
WhyLosing electrons gives a positive ion and gaining electrons gives a negative ion, because the balance between protons and electrons is changed.
7Multiple choice · Medium
A neutral atom has 17 protons and 18 neutrons. How many electrons does it have?
17
18
35
1
Tap an answer to check it.
WhyA neutral atom has equal numbers of protons and electrons, so it has 17 electrons. The number of neutrons does not affect electron count in a neutral atom.
8Multiple choice · Medium
When an unstable nucleus emits a beta particle, what change happens inside the nucleus?
A neutron turns into a proton
A proton turns into a neutron
Two protons and two neutrons leave the nucleus
An electron joins the nucleus
Tap an answer to check it.
WhyIn beta-minus decay a neutron changes into a proton and a fast-moving electron (the beta particle) is emitted, so the proton number increases by 1.
9Multiple choice · Medium
Which statement correctly describes the penetrating power of gamma radiation?
It is highly penetrating and needs thick lead or concrete to reduce it
It is stopped by a sheet of paper
It is stopped by a few centimetres of air
It is stopped by a thin sheet of aluminium
Tap an answer to check it.
WhyGamma radiation is the most penetrating; it is only partly absorbed by thick lead or several metres of concrete. Alpha is stopped by paper and beta by thin aluminium.
10Multiple choice · Medium
An alpha particle is the same as which of the following?
A helium-4 nucleus
A fast-moving electron
A high-energy electromagnetic wave
A single proton
Tap an answer to check it.
WhyAn alpha particle consists of two protons and two neutrons, which is identical to a helium-4 nucleus.
Ready to test yourself?
Practise Atomic structure with instant marking and per-topic score tracking.