10 O Half Yearly Assessment Diagnostic Quiz NHSPA

Label the components of an element cell.

a

b

c

d

Element Name

Chemical Symbol

Atomic Number

Atomic Mass

A group is a​ ​ (a)   on the periodic table. The ​ (b)   increases from ​​ (c)   to ​ (d)   .

• atomic number

• right

• column

• number of electron shells

• top

• bottom

• row

• left

Answer explanation

A group is a column on the periodic table. The number of electron shells increases from bottom to top.

A period is a​ (a)   on the periodic table. The ​ (b)   increases from ​ (c)   to ​ (d)   .

• row
• atomic number
• left
• right
• column
• number of electron shells
• top
• bottom

Valency of an element is the number of valence electrons that must be gained, lossed or shared to achieve a complete valence electron shell.

What is the valency of the following elements?

• 4

• Li

• 3

• N

• 2

• C

• 1

• O

• 2

• Ca

Which of the following accurately describes the chemical formula of the molecule shown above?

• 3CH₈O

• C₃H₇O

• C₄H₈O₂

• C₃H₈O

Answer explanation

The correct chemical formula is C3H8O because there are 3 carbon atoms, 8 hydrogen atoms, and 1 oxygen atom in the molecule shown above.

Which of the following molecules has the formula CH₂O?

• 
• 
• 
• 

How many neutrons are there for an atom with a mass of 20 and 11 protons?

• 9

• 11

• 20

• 31

Answer explanation

To find the number of neutrons, subtract the number of protons (11) from the mass number (20). Therefore, there are 9 neutrons in the atom.

Element number 22 (atomic number 22) has how many protons?

• 22

• 25

• 47

• 69

Answer explanation

Element number 22 (atomic number 22) has 22 protons because the atomic number represents the number of protons in an atom.

Atoms of the same element which have a different number of neutrons are called .

(a)  

• isotopes

• ions

• quarks

• molecules

Answer explanation

Atoms of the same element with different neutron numbers are called isotopes.

What is an isotope

• An atom with the same number of neutrons different number of protons

• An atom that has lost or gained an electron

• An atom with the same number of protons, different number of neutrons

• An atom with the same number of electrons and different neutrons

Answer explanation

An isotope is an atom with the same number of protons but a different number of neutrons, making it a variant of a chemical element.