Ask a New Question
Menu

Covalent bonds hold atoms together because they ...

(a) fill shells without giving atoms much charge.
(b) bring electrons closer to protons.
(c) use forces between nuclei as well as forces between electrons.
do all of the above.
do both (a) and (b).
Request Answer
Part B
In molecules, C, H, O, and N atoms usually make __, __, __, and __ bonds respectively.

3, 2, 4, 2
3, 2, 1, 4
4, 1, 3, 2
2, 1, 3, 4
4, 1, 2, 3
Request Answer
Part C
An atom's atomic number is 7. Its valence is most likely ...

2
1
5
7
3
Request Answer
Part D
By making two covalent bonds, an O atom (with 8 protons) fills its valence shell. Why does the atom's charge stay close to zero?

Shared electrons aren't always near oxygen.
The charge isn't near zero; it's -2.
The valence shell has 6 electrons.
The atom lost electrons from other shells.
The atom has 8 electrons.
Request Answer
Part E
In a double covalent bond, a carbon atom shares ...

both valence and nonvalence electrons.
two electrons.
electrons in two of its shells.
electrons in two orbitals.
None of the above.
Request Answer
Part F
The ammonia molecule in the diagram has the observed bond orientation because ...
A ball-and-stick model of ammonia. Three hydrogen atoms are attached to the nitrogen atom by single bonds.

N has four pairs of electrons in the valence shell.
N has 7 protons in its nucleus.
electrons repel one another.
All of the above.
None of the above.
Request Answer
Part G
Without making or breaking bonds, the pictured molecule can change its shape because ...
A ball-and-stick model of a molecule. The structure of the molecule, described from left to right, is four atoms that form a skeleton of the molecule like a Z-line. The first and the last atoms differ from each other and the middle atoms. The first three atoms bind to two small atoms each. The last atom binds to one small atom.

proximity of other atoms alters bond angles.
some atoms make longer bonds than others.
electrons can move from one bond to another.
rotation can occur around single bonds.
None of the above.
Request Answer
Part H
Two C atoms form a double bond. Each C is bound to two H atoms. Which statement is true?

All the atoms lie in a plane.
The bonds orient in a tetrahedral fashion.
The groups rotate around the C=C bond.
The bonds orient like tripods or pyramids.
All the atoms lie in a line.
Request Answer
Part I
Partial charges occur when ...

(a) a covalent bond links atoms of two kinds.
(b) atoms share electrons unequally.
(c) two ions are close together.
any of the above occur.
both (a) and (b).
Request Answer
Part J
To fill the valence shell, an electrically neutral, unbonded atom with atomic number 8 must add ...

1 electron.
8 electrons.
3 electrons.
2 electrons.
Can't tell without knowing which element it is.
Request Answer
Part K
Which answer helps to explain why carbon atoms tend to make 4 covalent bonds?

The carbon nucleus has 4 protons.
The first electron shell has 4 orbitals.
The valence shell needs 8 electrons.
All of the above.
None of the above; carbon makes 3 covalent bonds.
Request Answer
Part L
An electrically neutral molecule has the formula C3H4O2N. If the carbon atoms form the usual number of bonds, how many covalent bonds will each hydrogen atom have with other atoms in the molecule?

2
5
3
4
1

1 answer

Here are the answers to each part of your questions:

Part A
Covalent bonds hold atoms together because they ...
Answer: do all of the above.

  • Covalent bonds fill shells without giving atoms much charge (a), bring electrons closer to protons (b), and involve forces between nuclei and electrons (c).

Part B
In molecules, C, H, O, and N atoms usually make __, __, __, and __ bonds respectively.
Answer: 4, 1, 2, 3

  • Carbon (C) usually forms 4 bonds, Hydrogen (H) typically forms 1 bond, Oxygen (O) usually forms 2 bonds, and Nitrogen (N) usually forms 3 bonds.

Part C
An atom's atomic number is 7. Its valence is most likely ...
Answer: 5

  • An atom with atomic number 7 (like Nitrogen) has 5 valence electrons (it needs 3 more to fill its outer shell).

Part D
By making two covalent bonds, an O atom (with 8 protons) fills its valence shell. Why does the atom's charge stay close to zero?
Answer: The atom has 8 electrons.

  • Oxygen has 8 protons and typically shares electrons to fill its valence shell, resulting in no overall charge.

Part E
In a double covalent bond, a carbon atom shares ...
Answer: electrons in two orbitals.

  • A double bond consists of two pairs of shared electrons, which occupy two orbitals.

Part F
The ammonia molecule in the diagram has the observed bond orientation because ...
Answer: electrons repel one another.

  • The arrangement of the bonds is influenced by the repulsion between electron pairs in the valence shell.

Part G
Without making or breaking bonds, the pictured molecule can change its shape because ...
Answer: rotation can occur around single bonds.

  • Molecules can have flexibility and change shape due to rotational freedom around single bonds.

Part H
Two C atoms form a double bond. Each C is bound to two H atoms. Which statement is true?
Answer: All the atoms lie in a plane.

  • In a double bond, the involved atoms lie in the same plane due to the geometry of the double bond.

Part I
Partial charges occur when ...
Answer: both (a) and (b).

  • Partial charges are created when a covalent bond links atoms of two kinds (a), and when atoms share electrons unequally (b).

Part J
To fill the valence shell, an electrically neutral, unbonded atom with atomic number 8 must add ...
Answer: 2 electrons.

  • An atom with atomic number 8 (like Oxygen) has 6 valence electrons and needs 2 more to fill its valence shell.

Part K
Which answer helps to explain why carbon atoms tend to make 4 covalent bonds?
Answer: The valence shell needs 8 electrons.

  • Carbon needs 4 additional electrons to fill its valence shell (to achieve an octet).

Part L
An electrically neutral molecule has the formula C3H4O2N. If the carbon atoms form the usual number of bonds, how many covalent bonds will each hydrogen atom have with other atoms in the molecule?
Answer: 1

  • Each Hydrogen atom typically forms 1 covalent bond.

Feel free to ask if you have any further questions!