chemistry MCQs - 12th class Chapter 01 Mcqs

1

Who first arranged known elements into groups called Triads in 1829?

A

Newland

B

Al-Razi

C

Dobereiner

D

Mendeleev

2

The Modern Periodic Law states that the properties of elements are a periodic function of their...

A

Atomic Mass

B

Atomic Number

C

Valence Electrons

D

Atomic Size

3

The horizontal rows in the periodic table are known as...

A

Groups

B

Blocks

C

Families

D

Periods

4

In the modern periodic table, how many periods are there?

A

8

B

18

C

7

D

10

5

Elements in Group IA are called...

A

Halogens

B

Noble Gases

C

Alkaline Earth Metals

D

Alkali Metals

6

Which period(s) are referred to as short periods?

A

Period 1

B

Periods 2 and 3

C

Periods 4 and 5

D

Period 6

7

Elements of subgroups IIIA to VIIIA (except He) are known as...

A

s-block elements

B

d-block elements

C

p-block elements

D

f-block elements

8

The elements Lanthanides and Actinides belong to which block?

A

s-block

B

p-block

C

d-block

D

f-block

9

Which of the following is a metalloid?

A

Sodium (Na)

B

Chlorine (Cl)

C

Silicon (Si)

D

Lead (Pb)

10

What is the general trend of atomic radius as you move from left to right across a period?

A

Increases

B

Decreases

C

Remains constant

D

Increases then decreases

11

A positive ion is always ______ than its parent atom.

A

larger

B

smaller

C

the same size

D

heavier

12

The minimum energy required to remove an electron from an isolated gaseous atom is called...

A

Electron Affinity

B

Hydration Energy

C

Ionization Energy

D

Lattice Energy

13

How does ionization energy generally change when moving down a group?

A

It increases

B

It decreases

C

It remains the same

D

It fluctuates randomly

14

The addition of a second electron to a uninegative ion is a process that generally...

A

releases energy

B

absorbs energy

C

has no energy change

D

creates a neutral atom

15

Which property increases from top to bottom in a group of metals?

A

Ionization Energy

B

Non-metallic character

C

Metallic character

D

Electron Affinity

16

Oxides of non-metals, like SO3, are typically...

A

Basic

B

Acidic

C

Amphoteric

D

Neutral

17

Which element in the second period has the highest melting point due to its giant covalent structure?

A

Lithium (Li)

B

Oxygen (O)

C

Carbon (C)

D

Neon (Ne)

18

What is the oxidation state of an element in its free, uncombined state?

A

+1

B

-1

C

0

D

Depends on the group

19

The elements of Group IB (Cu, Ag, Au) are also known as...

A

Alkali metals

B

Halogens

C

Coinage metals

D

Noble gases

20

Halides of Group IA elements, like NaCl, are predominantly...

A

Covalent

B

Ionic

C

Polymeric

D

Metallic

21

Binary compounds of hydrogen with other elements are called...

A

Oxides

B

Halides

C

Hydrides

D

Carbides

22

Oxides that exhibit both acidic and basic properties are known as...

A

Neutral oxides

B

Peroxides

C

Amphoteric oxides

D

Suboxides

23

According to the text, hydrogen is usually placed at the top of which group?

A

Group IVA

B

Group VIIA

C

Group IA

D

Group VIIIA

24

In 1864, who classified 62 elements based on the 'Law of Octaves'?

A

Dmitri Mendeleev

B

Dobereiner

C

Moseley

D

Newland

25

The improvement by Moseley in 1911 was the discovery of...

A

the neutron

B

atomic mass

C

the electron

D

atomic number

26

Transition elements are contained in which subgroups?

A

A subgroups

B

B subgroups

C

Both A and B

D

Neither A nor B

27

Period 6 contains a set of fourteen elements called...

A

Actinides

B

Halogens

C

Lanthanides

D

Metalloids

28

The family name 'Halogens' is given to elements of which group?

A

Group IA

B

Group IIA

C

Group VIIA

D

Group VIIIA

29

The classification into s, p, d, and f blocks is based on the...

A

number of neutrons

B

valence orbital in bonding

C

atomic mass

D

metallic character

30

On the periodic table, where are non-metals generally located?

A

Left hand side

B

Centre

C

Bottom

D

Upper right corner

31

The gradual reduction in the size of Lanthanides is called...

A

Actinide Contraction

B

Lanthanide Contraction

C

Shielding Effect

D

Metallic Contraction

32

A negative ion is always bigger than its parent atom due to...

A

increased nuclear charge

B

loss of an electron shell

C

repulsion between electrons

D

attraction to the nucleus

33

The first ionization energy of Magnesium (Mg) is ______ that of Sodium (Na).

A

lower than

B

equal to

C

higher than

D

unrelated to

34

In general, which group has the highest values of ionization energy?

A

Alkali Metals (IA)

B

Halogens (VIIA)

C

Alkaline Earth Metals (IIA)

D

Noble Gases (VIIIA)

35

Electron affinity generally ______ within a period with increasing atomic number.

A

decreases

B

increases

C

remains constant

D

becomes zero

36

The melting points of Group IA elements ______ from top to bottom.

A

increase

B

decrease

C

remain the same

D

increase then decrease

37

What is the oxidation state of sulfur (S) in H2SO4?

A

+2

B

-2

C

+6

D

+4

38

Carbon in the form of diamond is a non-conductor because its valence electrons are...

A

free to move

B

delocalized

C

tetrahedrally bound

D

in the d-orbital

39

Hydration energy depends highly on the ______ of the ions.

A

mass number

B

charge to size ratio

C

number of neutrons

D

boiling point

40

Among the halides of a metal, which type tends to be the most ionic?

A

Fluoride

B

Chloride

C

Bromide

D

Iodide

41

Hydrides of Group IA and the heavier members of Group IIA are...

A

ionic

B

covalent

C

intermediate

D

gaseous

42

The boiling points of covalent hydrides like H2O and HF are unexpectedly high due to...

A

van der Waal's forces

B

covalent bonding

C

ionic bonding

D

hydrogen bonding

43

Which of the following oxides is amphoteric?

A

Na2O

B

SO3

C

Al2O3

D

Cl2O7

44

The basicity of main group metal oxides generally ______ on descending a group.

A

decreases

B

remains constant

C

increases

D

becomes neutral

45

Hydrogen can form an H- ion, which is similar to the ions formed by...

A

Alkali metals

B

Group IVA elements

C

Halogens

D

Noble gases

46

The reaction 2Na + 2H2O -> 2NaOH + H2 is characteristic of which family?

A

Halogens

B

Alkali Metals

C

Noble Gases

D

Transition Metals

47

Elements in the center of the periodic table are known as...

A

Representative elements

B

Lanthanides

C

Transition elements

D

Non-metals

48

Periods 4 and 5, each consisting of eighteen elements, are called...

A

short periods

B

incomplete periods

C

normal periods

D

long periods

49

The radius of a Na+ ion (95pm) is smaller than a Na atom (157pm) because of...

A

addition of a shell

B

loss of the outermost shell

C

decreased nuclear charge

D

electron-electron repulsion

50

Which halide of period 3 has the highest melting point, indicating ionic character?

A

NaCl

B

MgCl2

C

AlCl3

D

SiCl4