Exercise/bonding between atoms
Kit Sam Lam Bing Yim Secondary School
Bonding between atoms
Exercise
1.
2.
3.
Write down the charges on the ions formed from atoms in the table below:
Atom
Charge on the ion formed
Mg (Atomic number = 12)
(a)
N (Atomic number = 7)
(b)
Al (Atomic number = 13)
(c)
Classify each of the following compounds as ionic or covalent.
Compound
Ionic/Covalent
Ammonia (NH3)
(a)
Magnesium chloride (MgCl2)
(b)
Water (H2O)
(c)
Sodium oxide (Na2O)
(d)
Consider the information concerning particle X and particle Y listed below:
Particle
Number of protons
Number of electrons
Number of neutrons
X
16
16
18
Y
16
18
18
Which of the following statements is correct?
4.
5.
A.
X and Y are atoms of the same element.
B.
X and Y are atoms of different elements.
C.
X is a cation of Y.
D.
Y is an anion of X.
Which of the following pairs of elements would combine to form an ionic compound?
A.
Calcium and fluorine
B.
Carbon and sulphur
C.
Nitrogen and oxygen
D.
Potassium and sodium
The atomic number of element X is 12. X reacts with element Y to form an ionic compound
with formula XY2. To which group of the periodic table does Y belong?
A.
Group I
B.
Group IV
C.
Group VI
D.
Group VII
P.1
Exercise/bonding between atoms
Kit Sam Lam Bing Yim Secondary School
Bonding between atoms
Exercise
6.
The mass number of atom X is 27. X forms a cation with 3 positive charges. Which of the
following combinations concerning the cation of X is correct?
7.
Number of protons
Number of neutrons
Number of electrons
A.
10
14
13
B.
13
10
14
C.
13
14
10
D.
14
13
10
Which of the following ions have the same number of electrons as a neon atom?
(1) Mg2+
(2) O2(3) Cl-
8.
A.
(1) and (2) only
B.
(1) and (3) only
C.
(2) and (3) only
D.
(1), (2) and (3)
Element X (atomic number 11) combines with element Y (atomic number 16) to form a
compound Z. Which of the following statements are correct?
(1) Z is an ionic compound.
(2) The chemical formula of Z is X2Y.
(3) When X combines with Y, each atom of X loses one electron.
9.
A.
(1) and (2) only
B.
(1) and (3) only
C.
(2) and (3) only
D.
(1), (2) and (3)
The atomic number of element X is 20. Which of the following statements concerning X are
correct?
(1) X can combine with oxygen to form an ionic compound.
(2) X is in Group II of the periodic table.
(3) X is stored in paraffin oil in the laboratory.
A.
(1) and (2) only
B.
(1) and (3) only
C.
(2) and (3) only
D.
(1), (2) and (3)
P.2
Exercise/bonding between atoms
Kit Sam Lam Bing Yim Secondary School
Bonding between atoms
Exercise
10. Predict the type of compound (ionic/covalent) formed when each of the following pairs of
elements combine. Draw electron diagrams for the compounds formed.
(Showing electrons in the outermost shells only.)
(a) Beryllium and fluorine
(b) Phosphorus and hydrogen
(c) Magnesium and oxygen
(d) Silicon and chlorine
(e) Carbon and oxygen
11. The following table give some information about W, X, Y and Z which represent particles of
some elements. These particles are either atoms or ions.
Particle
W
X
Number of
Mass
Atomic
number
number
14
7
7
9
9
10
protons
electrons
neutrons
Y
9
10
10
Z
19
19
20
(a) W exist as diatomic molecules. Draw an electrons diagram for its molecule, showing
electrons in the outermost shells only.
(b) What is the relationship between X and Y?
(c) X can form a compound with Z. Draw an electron diagram for the compound
12. The non-metallic element selenium (Se) has six outermost shell electrons in its atoms.
(a) To which group in the periodic table does selenium belong?
(b) Hydrogen selenide is a compound made up of hydrogen and selenium.
(i)
Predict the type of bonding present in hydrogen selenide.
(ii) draw an electron diagram for hydrogen selenide, showing electrons in the
outermost shell only.
P.3
Exercise/bonding between atoms
Kit Sam Lam Bing Yim Secondary School
Bonding between atoms
Suggested answers to exercise
1.
(a) 2 positive charges
(b) 3 negative charges
(c) 3 positive charges
2.
(a) Covalent
(b) Ionic
(c) Covalent
(d) Ionic
3.
D
4.
A
Calcium is a metal (金屬) and fluorine is a non-metal (非金屬). An ionic bond results
when metal atoms combine with non-metal atoms. The compound formed is an ionic
compound.
5.
D
6.
C
X loses 3 electrons to form a cation with 3 positive charges. Therefore the cation of X
contains 3 more protons than electrons.
7.
A
8.
D
(1) Element X is sodium and element Y is sulphur. They combine to form an ionic
compound.
(2) When elements X and Y react, two atoms of X are required to release the two
electrons needed by an atom of Y. Ions of X and Y are in the ratio of 2:1.
Therefore the chemical formula of Z is X2Y.
(3) An atom of X tends to lose one electron to obtain the electronic arrangement of a
stable neon atom.
9.
A
Element X is calcium. It reacts with oxygen (a non-metal) to form an ionic compound.
P.4
Exercise/bonding between atoms
Kit Sam Lam Bing Yim Secondary School
Bonding between atoms
10. (a) Ionic compound
Only electrons in the outermost shells are shown.
(b) Covalent compound
Only electrons in the outermost shells are shown.
(c) Ionic compound
Only electrons in the outermost shells are shown.
P.5
Exercise/bonding between atoms
Kit Sam Lam Bing Yim Secondary School
Bonding between atoms
10. (d) Covalent compound
Only electrons in the outermost shells are shown.
(e) Covalent compound
Only electrons in the outermost shells are shown.
11. (a)
(b) Y is an anion of X.
(c)
12. (a) Group VI
(b) (i)
Covalent bond
(ii)
P.6