Revision: KPT, Atomic Structure, Ionic Bonding

Which number is unique to an element?

(no two elements have this same number)

• Group number in Periodic Table

• nucleon (mass) number

• neutron number

• proton number

Answer explanation

Look the Periodic Table - the number of protons in an atom determines what element it is.

For example, an atom with 8 protons is oxygen.

The atomic structure of one atom of an element is as shown.

Which nuclide notation represents this atom?

• 
• 
• 
• 

Answer explanation

No. of protons = 6

No. of neutrons = 6

No. of electrons = 6

The nucleus of atom Z contains 78 protons and 117 neutrons.

What is the nucleon number of atom Z?

• 39

• 78

• 117

• 195

Answer explanation

Nucleon no. = no. of p + no. of n

The nucleus of atom X contains 34 protons and 45 neutrons.

Which nuclide notation represents atom X?

• 
• 
• 
• 

Answer explanation

nucleon no. = proton no. + neutron no. = 34 + 45 = 79

Which statement explains why isotopes of the same element have similar chemical properties?

• They have the same number of protons.

• They have the same number of electrons.

• They have different numbers of neutrons.

• They have different relative atomic mass.

Answer explanation

Isotopes undergo the same type of chemical reactions as they have the same number of electrons.

Which statement about these two atoms X and Y is correct?

• They are isotopes of the same element.

• They have the same number of neutrons.

• They belong to the same group in the Periodic Table.

• They belong to the same period in the Periodic Table.

Answer explanation

Electronic configuration of X: 2, 4

Electronic configuration of Y: 2, 5

Both atoms have 2 electron shells hence both belong to Period 2.

When an atom gains or loses electrons, it becomes a charged particle that is stable.

What is the charged particle called?

• atom

• ion

• molecule

• particle

Positive ions are formed when atoms …….1…….. electrons.

Negative ions are formed when atoms …….2…….. electrons.

• A

• B

• C

• D

Answer explanation

Recall: Electrons are negatively charged.

When an atom gains electron(s), it becomes a negatively charged ion.

When an atom loses electron(s), it becomes a positively charged ion.

When an atom gains or loses electrons, it becomes a charged particle that is stable.

What is the charged particle called?

• atom

• ion

• molecule

• particle

Which row represents an ion?

(Recall: An ion is formed when an atom gains or loses electron(s).)

• A

• B

• C

• D

Answer explanation

In an atom, no. of p = no. of e.

When an atom gains or loses electron(s) to form an ion, no. of p is not equal to no. of e anymore.