2.4 2.5 Ionic and Covalent Bonding

Which pair of elements form a compound by sharing electrons?

• carbon and chlorine

• lithium and iodine

• neon and oxygen

• potassium and bromine

An element Y reacts with chlorine to form an ionic compound of formula YCl. What is the electronic structure of Y?

• 2,7

• 2,8,1

• 2,8,2

• 2,8,7

Element Q has an electronic structure 2,5. Element R has an electronic structure 2,7.

What is formed when Q and R react?

• Covalent ; QR

• Covalent ; QR₃

• Ionic ; QR

• Ionic ; QR₃

The diagram below shows the electron arrangement in a molecule of the compound AX₂. Which pair of elements could A and X be?

• A: oxygen; X: hydrogen

• A: sulfur; X: hydrogen

• A: sulfur; X: chlorine

• A: oxygen; X: sulfur

Which of the following is not a property of carbon dioxide?

• high melting and boiling point

• low melting and boiling point

• cannot conduct electricity in any state

Carbon dioxide has a low melting point due to small amount of energy required to overcome weak ___________________ __________________ of attraction between molecules

hat is the total number of electrons involved in bonding?

A metal X and a non-metal Y react together to form an ionic compound XY₃. What is the charge on X?

• +

• 3+

• -

• 3-

Which substance has a structure held together by electrostatic forces of attraction between oppositely charged ions?

• A

• B

• C

• D

For lithium oxide, In solid state, the ions are held rigidly in fixed positions, and they cannot move about to carry electric current; While in molten state, the ions can _______ over each other and move about to carry electric current.