Module 2 - Atomic Structure and Isotopes , Compounds, formulae and equation

Question 1

What is the charge of a
proton?

Answer 1

1+

Question 2

What is the charge an
electron?

Answer 2

1-

Question 3

Which particle has the same
mass as proton?

Answer 3

Neutron

Question 4

Which two particles make up
most of atom’s mass?

Answer 4

Protons and neutrons

Question 5

Which letter is used to
represent the atomic number
of an atom?

Answer 5

Z

Question 6

What does the atomic number
tell about an element?

Answer 6

Atomic number = number of protons in
an atom

Question 7

Which letter represents the
mass number?

Answer 7

A

Question 8

How is mass number
calculated?

Answer 8

Mass number = number of protons +
number of neutrons

Question 9

How to calculate the number
of neutrons?

Answer 9

Number of neutrons = mass number -
atomic number

Question 10

Define isotope

Answer 10

Atoms of the same element with different
number of neutrons

Question 11

Why does different isotopes of
the same element react in the
same way? (2)

Answer 11

● Neutrons have no impact on the chemical
reactivity
● Reactions involve electrons, isotopes have
the same number of electrons in the same
arrangement

Question 12

What are ions?

Answer 12

Charged particles that is formed when an
atom loses or gains electrons

Question 13

What is the charge of the ion
when electrons are gained?

Answer 13

Negative
N.B - positive charge when electrons are lost
E.g. 3+ ion has lost 3 electrons

Question 14

What is the unit used to
measure atomic masses
called?

Answer 14

Unified atomic mass unit, u

Question 15

Define relative atomic mass

Answer 15

The weighted mean mass of an atom of
an element compared with one twelfth of
the mass of an atom of carbon -12

Question 16

What is the unit of relative
atomic mass?

Answer 16

No units

Question 17

Define relative isotopic mass

Answer 17

The mass of an atom of an isotope
compared with one twelfth of the mass of
an atom of carbon-12

Question 18

The relative isotopic mass is
same as which number?

Answer 18

Mass number

Question 19

What two assumptions are
made when calculating mass
number?

Answer 19

1. Contribution of the electron is neglected
2. Mass of both proton and neutron is taken
   as 1.0 u

Question 20

How to calculate the relative
molecular mass and relative
formula mass?

Answer 20

Both can be calculated by adding the
relative atomic masses of each of the
atom making up the molecule or the
formula

Question 21

What are the uses of mass
spectrometry? (3)

Answer 21

● Identify unknown compounds
● Find relative abundance of each isotope of an
element
● Determine structural information

Question 22

How does a mass
spectrometer work?

Answer 22

● The sample is made into positive ions.
● They pass through the apparatus and are
separated according to mass to charge ratio.
● A computer analyses the data and produces
mass spectrum.

Question 23

How is the group number
related to the number of
electrons?

Answer 23

Group number = number of electrons in
the outer shell

Question 24

Does the group number
indicates horizontal or vertical
column in the periodic table?

Answer 24

Vertical column

Question 25

Do metals usually gain or lose
electrons?

Answer 25

Lose electrons

Question 26

Which are the 4 elements that
don’t tend to form ions and
why?

Answer 26

The elements are beryllium, boron, carbon
and silicon
Requires a lot of energy to transfer outer shell
electrons

Question 27

What are molecular ions?

Answer 27

Covalently bonded atoms that lose or
gain electrons

Question 28

What is the charge of an
ammonium ion?

Answer 28

+1 → NH4+

Question 29

What is the charge of a
hydroxide ion?

Answer 29

-1 → OH-

Question 30

What is the charge of a nitrate
ion?

Answer 30

-1 → NO3-

Question 31

What is the charge of a
carbonate ion?

Answer 31

-2 → CO3^2-

Question 32

What is the charge of a sulfate
ion?

Answer 32

-2 → SO4^2-

Question 33

What is an empirical formula?

Answer 33

Simplest whole number ratio of atoms of
each element present in a compound

Question 34

How to calculate empirical
formula?

Answer 34

● Divide the amount of each element by its molar
mass
● Divide the answers by the smallest value obtained
● If there is a decimal, divide by a suitable number
to make it into a whole number