Unit 5

Question 1

Semi-metals

Answer 1

Silicon, Boron, Germanium

Question 2

In an NEUTRAL atom

Answer 2

Number of protons = number of electrons
Atomic number (Z) = number of protons in an atom of that element

Question 3

Mass number

Answer 3

= number of protons + number of neutrons
Number of neutrons in an atom = mass number - atomic number

Question 4

Isotopes

Answer 4

Different atoms of an element which have the the same number of protons but a different number of neutrons.

Examples:
Hydrogen: protium, deuterium, tritium
Carbon: carbon-12, carbon-13, carbon-14
Chlorine: chlorine-35, chlorine-37

Question 5

Chemical property will be affected by ……

Answer 5

Difference in the number of electrons

Question 6

Physical property will be affected by ……

Answer 6

Difference in the number of neutrons

Question 7

Relative isotopic mass of a particular isotope of an element

Answer 7

It is the mass of an atom of the isotope relative to 1/12 of the mass of a carbon-12 atom.

Question 8

Relative atomic mass of an element

Answer 8

It is the weighted mean mass of its atom, taking into account the relative abundance of each isotope present in a naturally occurring sample of the element, relative to 1/12 of the mass of a carbon-12 atom.

Question 9

Electron shells

Answer 9

Orbits

Question 10

Electronic arrangement

Answer 10

The number of electrons in each shell

Question 11

Atomic number

Answer 11

= number of protons of an element
= number of electrons in a neutral atom