The electronic configuration of an element X is 1s²2s ²2s⁶3p ² 3p⁴. It can be deduced that X

A. Belongs to group 6 of the Periodic Table

B. Belongs to group IV of the Periodic Table

C. has 3 unpaired electrons in its atom

D. has relative molecular mass of 16

What is the mass number of an element having 20 neutrons, 15 protons and 15 electrons?

A. 15

B. 30

C. 35

D. 50

Which of the following sets of elements are arranged in order of decreasing atomic size in the Periodic Table?

A. ₆C, ₄Be, ₇N,₈ O

B. ₄Be,₆ C,₇ N,₈ O

C. ₈O, ₇ N, ₆C, ₄Be

D. ₇N, ₈O, ₆C,₄BeBe

Which of the following changes is characteristic of an alpha-particle emission?

A. the nucleus loses two protons and two neutrons

B. a proton combines with an electron giving off heat

C. the nucleus splits into two equal parts

D. four neutrons are lost

An element X has an atomic number of 16. What is its most likely oxidation state in its binary compounds?

A. -3

B. -2

C. +2

D. +4

An element which can exist in two or more forms in the same physical state, exhibits

A. isotopy

B. structural isomerism

C. allotropy

D. variable valency

Which of the following can be used to predict the type of bonding in HCI?

A. pH value

B. Electronegativity difference

C. Heat of neutralization

D. Heat of solution

Which of the following molecules has a linear structure?

A. NH₃

B. H₂O

C. CO₂

D. CH₄