Applied Science Chemistry

Question 1

How many electrons can fit into each of the first, second, third, and fourth shells?

Answer 1

1st - 2 (1s)

2nd- 8 (2s 2p)

3rd - 18 (3s 3p 3d)

4th - 32 (4s 4p 4d 4f)

Question 2

How many electrons can fit into an orbital?

Answer 2

2

Question 3

How many electrons can fit

into a single p orbital?

Answer 3

All single orbitals can hold 2 electrons.

Question 4

How many electrons can fit into

a set of p orbitals?

Answer 4

There are 3 p orbitals in a set, so it will hold a total of 6 electrons.

Question 5

What is an ionic bond?

Answer 5

An ionic bond is the strong electrostatic attraction between a positive ion and a negative ion.

Question 6

What is a cation?

Answer 6

A positive ion.

Question 7

What is an anion?

Answer 7

A negative ion.

Question 8

How is a cation formed?

Answer 8

A metal atom loses electrons.

Group 1 metals become +1.

Group 2 metals become +2.

Question 9

How are anions formed?

Answer 9

Non-metals form anions when they gain electrons.

For example: F^-, Cl^-, O^2-

Question 10

What influences the strength of an ionic bond?

Answer 10

The strength of the bond depends on the ionic radius (size of the ions)

and the charge on the ions.

Smaller radius gives a stronger bond.

Greater charge gives a stronger bond.

Question 11

What is a covalent bond?

Answer 11

The electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms.

Question 12

How can you tell if the bonding is ionic or covalent by looking at the molecular formula or the name of a compound?

Answer 12

Metal + Non-metal is ionic bonding.

Non-metal + non-metal is covalent bonding.

Question 13

What is the formula for a nitrate ion?

Answer 13

NO₃^-

Question 14

What is the formula for the carbonate ion?

Answer 14

CO₃^2-

Question 15

What is the formula for the sulfate ion?

Answer 15

SO₄^2-

Question 16

What is the formula for a hydroxide ion?

Answer 16

OH^-

Question 17

What is the formula for the

ammonium ion?

Answer 17

NH₄⁺

Question 18

What is the charge on a zinc ion?

Answer 18

Zn²⁺

Question 19

What is the charge on a silver ion?

Answer 19

Ag⁺

Question 20

What charge do the following metals have when they are ions:

H, Li, Na, K, Rb, Cs, and Fr.

Answer 20

They are all in Group 1, so they all have a +1 charge:

H⁺, Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺, and Fr⁺

Question 21

What charge do the following metals have when they are ions:

Be, Mg, Ca, Sr, Ba, and Ra.

Answer 21

They are all in Group 2, so they all

have a +2 charge:

Be²⁺, Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺, and Ra²⁺.

Question 22

What is the charge on the following non-metals when they are ions:

F₂, Cl₂, Br₂, I₂, and As_2..

Answer 22

They are all in Group 7, so they all have a 1- charge.

(They need one more electron to make 8, a full outer shell).

F^-, Cl^-, Br^-, I^-, and As^-

Question 23

What is the charge on an oxygen ion?

Answer 23

Oxygen is in Group 6 so it needs 2 more electrons to make 8 for a full outer shell. Therefore it has a -2 charge: O^2-

Question 24

Name the three types of bonding.

Answer 24

Ionic (metal + non-metal)

Covalent (non-metal + non-metal)

Metallic (metals on their own)

(Do not include hydrogen bonding in the 3 main types of bonding. H bonds are intermolecular forces.)

Question 25

What is a **lone pair**?

Answer 25

A lone pair is a non-bonding pair of electrons.

Question 26

What are **delocalised electrons**?

Answer 26

Electrons that are free to move. There are delocalized electrons in metallic structure which is why metals conduct electricity.

Question 27

What is the term for the attraction or repulsion between neighboring molecules.

Answer 27

Intermolecular Forces

Question 28

What is a **dipole**?

Answer 28

The separation of charges within a covalent molecule. (One end of the molecule is slightly positive and the other end is slightly negative.)

Question 29

**Van der Waals forces** is another term for what?

Answer 29

Intermolecular forces.

Question 30

Water has some unusual properties including a high melting and boiling point. Why?

Answer 30

Water forms **hydrogen bonds**.

Question 31

When do **hydrogen bonds** form?

Answer 31

When there is a **lone pair** of electrons that can attract a **hydrogen**. Oxygen and Nitrogen have lone pairs. If the molecules have either oxygen or nitrogen and there is also hydrogen, then hydrogen bonds will form.

Question 32

Define the term **mole**.

Answer 32

A unit of substance equivalent to the number of atoms in 12g of carbon-12.

Question 33

What is **molar mass (Mr)**?

Answer 33

Molar mass is the mass of one mole of a substance.