Chlorine, bromine and iodine belong to the same group and

A. are gaseous at room temperature.

B. form white precipitate with AgNO_3(aq)

C. react violently with hydrogen without heating

D. react with alkali

Which of the following elements can conveniently be placed in two groups in the periodic table ?

A. Carbon

B. Copper

C. Hydrogen

D. Oxygen

The bond formed when two electrons that are shared between two atoms are donated by only one of the atoms is

A. covalent

B. dative

C. ionic

D. metalic

When element ₂₀A combines with element ₈Y,

A. a covalent compound, AY is formed

B. an ionic compound AY is formed

C. an ionic compound, A₂Y is formed

D. a covalent compound, _AY₂ is formed

In metallic colids, the forces of attraction are between the mobile valence electrons and

A. atoms

B. neutrons

C. the negative ions

D. positively charged nuclei

Which of the following statements about displacement reaction is correct?

A. A more electropositive element displaces a less electroposive one

B. A less electropositive element displaces a more electropositive one

C. The position of elements in the reactivity series has no effect on the reaction

D. it only occurs when the reaction is at equilibrium

The volume occupied by 17g of H₂S at s.t.p. is [H = 1.00, S = 32.0, Molar volume = 22.4 dm³]

A. 11.2dm ³

B. 17.0 dm³

C. 34.0dm ³

D. 44.8dm ³

Consider the reaction represented by the following equation: xKMnO _4(aq) + ySO_2(g) + zH₂O_(I) → K ₂SO_4(AQ) + 2MnSO_4(aq) + 2H₂SO x,y and z are respectively

A. 2,5 and 2

B. 2,2 and 5

C. 5, 1 and 2

D. 1, 5 and 2

What is the amount of magnesium that would contain 1.20 x 10²⁴ particles? [Mg = 24, Avogadro's constant = 6.02 x 10²³]

A. 0.5 moles

B. 2.0 moles

C. 12.0 moles

D. 24.0 moles

The number of atoms in one mole of a substance is equal to the

A. mass number

B. oxidation number

C. atomic number

D. avogadro number