Which species contains the same number of neutrons as and the same number of electrons as ?
The elements phosphorus, sulfur and chlorine are in Period 3 of the Periodic Table.
Table 1.1 shows some properties of the elements P to Cl .
The first ionisation energy of S is not shown.

Table 1.1
P3−,S2− and Cl−have the same number of electrons.
State the trend in ionic radius shown by P3−,S2− and Cl−.
Explain your answer.
Use of the Data Booklet is relevant to this question.
In which option do all three particles have the same electronic configuration and the same number of neutrons?
15 N3−16O2−19 F−
18O2−19 F−20Ne
19 F−20Ne23Na+
22Ne23Na24Mg2+
Atoms with nuclei containing an odd number of protons tend to have fewer isotopes than those with an even number of protons.
Gallium has two stable isotopes, 69Ga and 71Ga.
Complete Table 1.1 to show the numbers of protons, neutrons and electrons in the two stable isotopes of gallium.

Table 1.1
Species such as NH4+,CO32− and PO43− are examples of molecular ions.
Complete Table 1.1 to show the total numbers of protons and electrons in the molecular ions NH4+,CO32− and PO43−.

Table 1.1
In which species are the numbers of protons, neutrons and electrons all different?
919 F−
1123Na+
1531P
1632 S2−
The ion Y3− contains 18 electrons and has a mass number of 31.
How many protons and neutrons does Y3− contain?
protons
neutrons
15
16
15
18
18
13
21
10
Atoms contain the subatomic particles electrons, protons and neutrons. Protons and electrons were discovered by observations of their behaviours in electric fields.
The diagram shows the behaviour of separate beams of electrons and protons in an electric field.

Complete the diagram with the relative charge of each of the electrically charged plates.
On the diagram, draw a line to show how a separate beam of neutrons from the same source behaves in the same electric field.
In which pair do the atoms contain the same number of neutrons?
11 B and 12C
7Li and 9Be
24Mg and 28Si
14 N and 16O
The model of the nuclear atom was first proposed by Ernest Rutherford. He developed this model on the basis of results obtained from an experiment using gold metal foil.
Complete the table with information for two of the particles in an atom of 197Au.

