What is the chemical symbol for the element mercury?
Hg
What is the formula of water?
H2O
An atom has 13 protons and 14 neutrons. What is its mass number?
27
An atom has an atomic number of 9 and a mass number of 19. What are its numbers of protons, neutrons and electrons?
protons : 9, electrons : 9 and neutrons : 10
What are isotopes?
Atoms of the same element with different numbers of neutrons
Four atoms have the numbers of protons and neutrons given below. Which two atoms are isotopes of the same element? W : 8 protons and 8 neutrons, X : 8 protons and 10 neutrons, Y : 10 protons and 8 neutrons, Z : 9 protons and 10 neutrons
W & X
What is the best definition of the mass number of an element?
The total number of protons and neutrons in its atoms
In the current model of the atom, what are the two particles that are present in the nucleus?
Protons and neutrons
Uranium-235 has 92 protons. How many neutrons does it have?
143
Nitrogen-14 has 7 protons. How many neutrons does it have?
7
The atomic number of an element is …
The number of protons
What has an ionised atom lost or gained?
Electrons
An alpha particle is…
A helium nucleus
What is nuclear fission?
The splitting of a heavy nucleus
Lithium-6 has 3 protons. How many neutrons does it have?
3
