Chapter 1: Atoms & Atom Model - Science Mcqs for Grade 7 - Set 1

1)   To find out number of neutrons in an atom, we need to know the

a. atomic number
b. proton number
c. electron number
d. mass number
Answer  Explanation 

ANSWER: mass number

Explanation:
No explanation is available for this question!


2)   The attraction of two ions due to opposite charge is known as

a. ionic bonding
b. covalent bonding
c. metallic bonding
d. dative bonding
Answer  Explanation 

ANSWER: ionic bonding

Explanation:
No explanation is available for this question!


3)   To trace the path of phosphorus, the isotope of phosphorus which is added to the fertilizers, is

a. Phosphorus-31
b. Phosphorus-32
c. Phosphorus-33
d. Phosphorus-34
Answer  Explanation 

ANSWER: Phosphorus-32

Explanation:
No explanation is available for this question!


4)   If the mass of protons and neutrons is 1, then the mass of electron is

a. 2
b. 2-Jan
c. 4-Jan
d. 1/1890
Answer  Explanation 

ANSWER: 1/1890

Explanation:
No explanation is available for this question!


5)   The name of physicist who discovered the nucleus of atom was

a. Democritus
b. John Dalton
c. Ernest Rutherford
d. Vander Waals
Answer  Explanation 

ANSWER: Ernest Rutherford

Explanation:
No explanation is available for this question!


6)   Sodium ion has

a. positive charge
b. negative charge
c. no charge
d. may be positive or negative
Answer  Explanation 

ANSWER: positive charge

Explanation:
No explanation is available for this question!


7)   Radioactive particles give off

a. waves
b. rays
c. energy
d. light
Answer  Explanation 

ANSWER: rays

Explanation:
No explanation is available for this question!


8)   The formula that shows the number and kind of atoms which a substance of a molecule contained, is known as

a. chemical formula
b. atomic formula
c. compound formula
d. molecular formula
Answer  Explanation 

ANSWER: chemical formula

Explanation:
No explanation is available for this question!


9)   Sodium becomes a cation when

a. it loses a proton
b. it gains a proton
c. it loses an electron
d. it gains an electron
Answer  Explanation 

ANSWER: it loses an electron

Explanation:
No explanation is available for this question!


10)   The symbol of potassium is

a. Po
b. K
c. Ps
d. Pa
Answer  Explanation 

ANSWER: K

Explanation:
No explanation is available for this question!


11)   Electrons have

a. negative charge
b. positive charge
c. no charge
d. both charges
Answer  Explanation 

ANSWER: negative charge

Explanation:
No explanation is available for this question!


12)   As compare to ionic compounds, covalent bond has

a. high melting but low boiling point
b. low melting but high boiling point
c. low melting and boiling point
d. high melting and boiling point
Answer  Explanation 

ANSWER: low melting and boiling point

Explanation:
No explanation is available for this question!


13)   Ionic bonds are

a. easy to break
b. weak
c. electrical bonds
d. very difficult to break
Answer  Explanation 

ANSWER: very difficult to break

Explanation:
No explanation is available for this question!


14)   Valency of sodium is

a. 1
b. 4
c. 3
d. 2
Answer  Explanation 

ANSWER: 1

Explanation:
No explanation is available for this question!


15)   Neutrons in an atom also affect the

a. chemical properties
b. physical properties
c. bonding properties
d. thermal properties
Answer  Explanation 

ANSWER: physical properties

Explanation:
No explanation is available for this question!


16)   Atoms of sodium and chlorine are stuck by chemical glue which is known as

a. bond
b. alpha gum
c. force of glue
d. atomic gum
Answer  Explanation 

ANSWER: bond

Explanation:
No explanation is available for this question!


17)   A large amount of heat is produced in power plants when energy is released which turns

a. black rods into orange
b. water into steam
c. ice into water
d. acid into alkali
Answer  Explanation 

ANSWER: water into steam

Explanation:
No explanation is available for this question!


18)   In nuclear power plants, energy is released

a. quickly
b. slowly
c. normally
d. very quickly
Answer  Explanation 

ANSWER: slowly

Explanation:
No explanation is available for this question!


19)   The symbol of "Boron" is

a. Bo
b. C
c. N
d. Br
Answer  Explanation 

ANSWER: Bo

Explanation:
No explanation is available for this question!


20)   The symbol of "Helium" is

a. H
b. He
c. Na
d. Hy
Answer  Explanation 

ANSWER: He

Explanation:
No explanation is available for this question!