4.2

Which statements about covalent bonding are correct ?

I. Covalent bonds are formed by the electrostatic attraction between shared pairs of electrons and the positively charged nuclei on either side of the electrons.

II. Covalent bonds are directional.

III. Double bonds are always stronger than single bonds between the same two atoms.

• I and II only

• I and III only

• II and III only

• I, II and III

Tags

NGSS.HS-PS1-1

Which molecule contains the shortest distance between adjacent oxygen atoms in the molecule?

• oxygen, O₂

• ozone, O₃

• hydrogen peroxide, H₂O₂

• tert-butyl hydroperoxide, (CH₃)₃ COOH

Which substance will contain the strongest bond between the two carbon atoms?

• ethyne, HCCH

• ethene, H₂CCH₂

• ethane, H₃CCH₃

• chloroethene, H₂CCHCl

Tags

NGSS.HS-PS1-4

Which compound will contain the most polar bond?

• ethene, H₂CCH₂

• chlorethane, H₃CCH₂Cl

• ethane, H₃CCH₃

• bromorethane, H₃CCH₂Br

Which statement explains why a covalent bond between two different atoms is polar?

• One atom has gained one or more electrons and the other has lost one or more electrons.

• The bonding pair of electrons are attracted more strongly towards the more electronegative atom resulting in an unequal distribution of charge.

• The electrons are attracted to the atom which has the greatest atomic mass resulting in an unequal distribution of charge.

• The bonding pair of electrons are attracted more strongly to the atom with the less negative value of electron affinity resulting in an unequal distribution of charge

The structure of ethanoic acid is shown and the two carbon to oxygen bonds are labelled x and y.

Which is a correct statement about x and y?

• x is weaker and shorter than y.

• x is stronger and longer than y.

• x is weaker and longer than y.

• x is stronger and shorter than y.

Tags

NGSS.HS-PS1-2

NGSS.HS-PS1-3

The group 1 element sodium reacts with the group 17 element chlorine to form sodium chloride, which is ionic. The IB periodic table shows hydrogen as also being in group 1. Which factor correctly explains why the bonding in hydrogen chloride is covalent, not ionic?

• Hydrogen atoms are too small to form an ion with chlorine.

• Unlike sodium, hydrogen has no inner shell of electrons so cannot lose its valence electron to form an ion.

• Hydrogen is much more electronegative than sodium so does not completely lose its valence electron when it bonds to chlorine.

• Hydrogen has the configuration 1s¹ so will gain an electron to form 1s² , the electron configuration of the noble gas helium, when it bonds to chlorine.

Tags

NGSS.HS-PS1-2

Which contain polar bonds?

I. carbon dioxide, CO₂

II. ammonia, NH₃

III. methane, CH₄

• I and II only

• I and III only

• II and III only

• I, II and III only

Which diagrams correctly show all the bond polarities?

• I and II only

• I and III only

• II and III only

• I, II and III only

Tags

NGSS.HS-PS1-1

Which compound contains both ionic and covalent bonding?

• Ca(OH)₂

• SiCl₄

• PbCl₂

• C₂H₅OH