ExRev2

Which one of the following statements is true?

• An element cannot be a liquid.

• All pure substances are elements.

• The smallest possible particle of an element is a proton.

• All compounds consist of two or more elements

Which of the following symbols represents an atom with the greatest number of neutrons?

• 
• 
• 
• 

When a sodium atom (Na) becomes a sodium ion (Na⁺) the _________.

• ion has the same number of electrons but fewer protons.

• ion has the same number of protons but fewer electrons.

• ion has the more electrons and a larger atomic mass.

• ion has the fewer electrons and a smaller atomic mass.

Element Y is in group 17 and period 2 of the periodic table. Which statement is correct?

• Y has 17 occupied energy levels.

• Y can form ions with 2– charge.

• Y is a Noble gas.

• Y has 7 valence electrons.

• H₂O

• Al

• Al(OH)₃

• Al₂(OH)₃

The formula for iron(III) sulfate is Fe₂(SO₄)₃. What is the total number of each atom in iron(III) sulfate?

• 2 atoms of Fe

  1 atom of S

  4 atoms of O

• 2 atoms of Fe

  1 atom of S

  12 atoms of O

• 2 atoms of Fe

  3 atom of S

  12 atoms of O

• 6 atoms of Fe

  3 atom of S

  12 atoms of O

The correct formula for a chlorate ion is

• Cl^–

• C₂H₃O₂^–

• ClO₃^–

• C₂O₄^2–

A metallic element ‘Q’ combines with phosphorus, forming an phosphide with the formula Q₃P_2. The formula for the compound of this same metal with fluorine would be

• QF

• QF₂

• QF₃

• Q₂F₃

Which answer has a coefficient of 3 and represents 6 oxygen atoms?

• 3O₃(g)

• 3KNO₃(aq)

• 3CO₂(g)

• CH₄O₃(s)

• 50

• 52

• 53

• 52.795