Which of the statements about the behaviour of the atom is correct?

A. atomic size decreases down the group

B. atomic size increases across the period

C. anions are smaller than the parent atom

D. cations are smaller than the parent atom

Which of the following properties of covalent compounds is not correct? They

A. are non-electrolytes

B. are mostly gaseous and volatile liquids

C. have low melting point

D. have high boiling points

Which of the following arrangements is in order of increasing ionization energy?

A. AI, Si, P, S

B. Si, AI,S,P

C. S,P,Si,AI

D. P, Si,S,AI

In bonded atoms, increase in electronegativity difference,

A. increases polarity

B. decreases polarity

C. has no effect on polarity

D. brings the polarity to zero

Which of the following molecules is not linear in shape?

A. CO₂

B. O ₂

C. NH₃

D. HCI

The number of particles in one mole of a chemical compound is the

A. atomic number

B. avogadro's number

C. mass number

D. oxidation number

How many molecules are there in 14 g of nitrogen at s.t.p.? [N = 14, Avogadro's constant = 6.02 x 10²³ mol^-1]

A. 6.02 x 10²³

B. 3.01 x 10²³

C. 8.43 x 10²⁴

D. 1.20 x 10²⁴

Consider the reaction represented by the equation: 2NaHCO₃ → Na₂CO ₃ + H ₂O + CO ₂. What is the mass of sodium trioxocarbonate (lV) produced by the complete decomposition of 33.6 g of sodium hydrogen trioxocarbonate (IV)? [NaHCO₃ = 84, Na₂CO₃ = 106]

A. 10.6 g

B. 16.8 g

C. 21.2 g

D. 42.4 g

What is the percentage by weight of calcium in Ca(OCI)₂? [Ca = 40, Cl = 35.5, O = 16]

A. 28.0%

B. 31.6%

C. 43.8%

D. 44.5%

What is the value of -14^oC on the Kelvin temperature scale?

A. 259K

B. 287 K

C. 287^oK

D. 259^oK