Chemistry 9th Chap 3 : Topic 5 - Maryam Publications

Chemistry Chapter 3 : Topic 5

Mass–Charge Relationships

1 / 20

A student claims that the identity of an element depends mainly on the number of neutrons present in its nucleus. Which statement correctly evaluates this claim based on the properties of subatomic particles?

A) The claim is correct because neutrons balance the nuclear charge.

B) The claim is incorrect because electrons determine the atomic mass.

C) The claim is incorrect because protons determine the atomic number and identity.

D) The claim is correct because neutrons contribute the most mass.

2 / 20

Which statement best explains why electrons have negligible contribution to atomic mass but a significant role in chemical behavior?

A) Electrons are heavier than protons but less reactive.

B) Electrons are neutral and exist outside the nucleus.

C) Electrons have very small mass but are involved in bonding due to their negative charge.

D) Electrons have no mass but large positive charge.

3 / 20

If a neutral atom loses one electron, how does its charge and mass change?

A) Charge becomes positive, mass increases

B) Charge becomes positive, mass remains almost unchanged

C) Charge becomes negative, mass decreases significantly

D) Charge remains neutral, mass decreases

4 / 20

Which comparison correctly represents the relationship between mass and charge of proton, neutron, and electron?

A) Electron has equal mass to proton but opposite charge

B) Neutron has no mass but positive charge

C) Proton is lighter than electron but has positive charge

D) Proton and neutron have equal mass; electron has negligible mass and negative charge

5 / 20

A particle is observed to have a mass approximately equal to that of a proton but carries no charge. What is this particle?

A) Positron

B) Proton

C) Electron

D) Neutron

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Which statement best describes the role of neutrons in an atom considering their mass and charge?

A) They reduce atomic mass due to zero charge

B) They determine atomic number

C) They determine chemical properties due to negative charge

D) They stabilize the nucleus without contributing to charge

7 / 20

Two atoms have the same number of protons but different numbers of neutrons. Which conclusion is correct regarding their mass and charge?

A) Different mass, same charge

B) Same mass, same charge

C) Different mass, different charge

D) Same mass, different charge

8 / 20

Why does removing a neutron from an atom not affect its electrical charge?

A) Neutrons are negatively charged

B) Neutrons are located outside the nucleus

C) Neutrons are equal in number to electrons

D) Neutrons carry no charge

9 / 20

Which statement correctly explains the relationship between mass number and subatomic particles?

A) Mass number = number of neutrons only

B) Mass number = number of protons + neutrons

C) Mass number = number of electrons + neutrons

D) Mass number = number of protons + electrons

10 / 20

An atom has 6 protons, 6 neutrons, and 6 electrons. Which statement correctly describes its charge and mass?

A) Positively charged with equal contribution from all particles

B) Negatively charged with mass mainly from neutrons

C) Neutral atom with mass mainly from protons and neutrons

D) Neutral atom with mass mainly from electrons

11 / 20

Which of the following changes will significantly affect the mass of an atom but not its charge?

A) Adding an electron

B) Adding a neutron

C) Removing a proton

D) Removing an electron

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A species has 11 protons, 11 electrons, and 12 neutrons. What is its overall charge and approximate mass relation?

A) Positive, mass mainly from neutrons

B) Neutral, mass mainly from protons and neutrons

C) Neutral, mass mainly from protons

D) Negative, mass mainly from electrons

13 / 20

Which statement best explains why protons and electrons have equal but opposite charges?

A) To maintain balance and neutrality in atoms

B) Because neutrons neutralize both

C) To increase atomic mass

D) Because electrons are heavier than protons

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Which particle contributes the least to atomic mass and why?

A) Electron, due to very small mass

B) Proton, due to positive charge

C) All contribute equally

D) Neutron, due to neutrality

15 / 20

If an atom gains two electrons, what will be the effect on its charge and mass?

A) Charge becomes negative, mass decreases

B) Charge remains neutral, mass unchanged

C) Charge becomes positive, mass increases significantly

D) Charge becomes negative, mass increases slightly

16 / 20

Which of the following correctly matches a particle with its relative mass and charge?

A) Proton: mass 1, charge + 1

B) Neutron: mass 0, charge 0

C) Electron: mass 1/1, charge - 1

D) Electron: mass 1, charge + 1

17 / 20

Why are isotopes of the same element chemically similar despite having different masses?

A) They have different electrons

B) They have same number of protons and electrons

C) They have different charges

D) They have different neutrons affecting bonding

18 / 20

Which conclusion can be drawn if two particles have equal mass but different charges?

A) They must both be neutrons

B) They are likely proton and neutron

C) They are electrons

D) They are isotopes

19 / 20

Which statement correctly explains the dominance of nuclear mass in an atom?

A) Protons and neutrons are concentrated in nucleus and are heavy

B) Electrons contribute most due to their number

C) Electrons are located in nucleus

D) Neutrons have zero mass

20 / 20

A particle has a charge of - 1 and negligible mass. What role does it primarily play in an atom?

A) Stabilizes nucleus

B) Determines atomic number

C) Participates in chemical bonding

D) Determines mass number

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