Chemistry Mock

Which statements about isotopes of the same element are correct?

• 1 and 2

• 1 and 3

• 2 only

• 3 only

The table shows the electron arrangement of four atoms.

which two atoms combine to form a covalent compound?

• W and X

• W and Y

• X and Y

• X and Z

Which statement describes the attractive forces between molecules?

• they are strong covalent bonds which hold molecules together

• they are strong ionic bonds which hold molecules together

• they are weak forces formed between covalently-bonded molecules

• they are weak forces which hold ions together in a lattice

The diagram represents the general structure of a solid Z.

What is Z?

• aluminium

• iodine

• silicon dioxide

• sulphur

A compound X, contains 40.0% carbon, 6.7% hydrogen and 53.3% oxygen by mass. The relative molecular mass of X is 60. What is the molecular formula of X?

• CH₂O

• CH₄O

• C₂H₄O

• C₂H₄O₂

Which statement about the Periodic Table is correct?

• elements in the same period have the same number of valence electrons

• the elements on the left are usually gases

• the most metallic elements are on the left

• the relative atomic mass of the elements increases from right to left

Why is argon used to fill electric lamps?

• it conducts electricity

• it glows when heated

• it is less dense than air

• it is not reactive

An element melts at 1455^oC, has a density of 8.90g/cm³ and forms a green chloride. Where in the Periodic Table is this element found?

• A

• B

• C

• D

In the molecules CH₄, HCl and H₂O, which atoms use all of their outer shell electrons in bonding?

• C and Cl

• C and H

• Cl and H

• H and O

Different quantities of nitrogen monoxide (NO) are listed below. Which one contains the least number of molecules?

• 6 X 10³ cm³ at STP

• 6 X 10²³ molecules

• 6 X 10^-1 g

• 6 mol