Chemical reactions

Question 1

Why are He, Ne and Ar considered noble gases?

Answer 1

They all have completely filled valence shells. Thus they are stable, unreactive and called Noble gases

Question 2

What is a chemical reaction?

Answer 2

It is a rearrangement of atoms to form new compounds as they try to achieve stability (by combining with another atom)

Question 3

What is ionic bonding?

Answer 3

The complete transfer of electrons from a metal to a non-metal to form ions which attract each other via an electrostatic force of attraction.

Question 4

Exampled of ionic bonding

Answer 4

Mg + F —-> MgF2 (magnesium fluoride)
Na+O——->Na2O (sodium oxide)
Na+Cl——–>NaCl (sodium chloride)
Mg+S———->MgS (magnesium sulfide)

Question 5

What is covalent bonding?

Answer 5

Covalent Bonding takes place between two or more non-metal atoms, it involves the sharing of electrons facilitated by overlapping of electron clouds, the electrons are held in between the two atomic nuclei

Question 5

What is covalent bonding?

Answer 5

Covalent Bonding takes place between two or more non-metal atoms, it involves the sharing of electrons facilitated by overlapping of electron clouds, the electrons are held in between the two atomic nuclei

Question 6

What is a diatomic and the types of bonds?

Answer 6

Diatomic- Covalent bonding between similar non metal atoms. Some non-metal elements exist as simple covalent molecules
- A single covalent bond has one pair of electrons as found on the overlap
-A double covalent bond has two pairs of electrons on the overlap
- A triple covalent bond has three pairs of electrons on the overlap

Question 7

What are Diatomic molecules?

Answer 7

Diatomic molecules contain two atoms that are chemically bonded by exchanging valencies

Question 8

List all Diatomics (7)
honclebrif

Answer 8

H2- single bond
O2- double bond
N2- triple bond
Cl2- single bond
Br2- single bond
I2- single bond
F2- single bond
pronounced honclebrif

Question 9

Examples of Covalent bonding

Answer 9

S+F —> SF2 (sulfur difluoride)
C+Cl —-> CCl4 (carbon tetrachloride)
N+H —-> NH3 (Ammonia)
H+Cl —-> HCl (hydrogen chloride) - diatomic
O+F —–> OF2 (oxygen difluoride)
Si + F —–> SiF4 (silicon tetrafluoride)
Na + P —–> Na3P (sodium phosphate)

Question 10

What is Metallic bonding?

Answer 10

In metallic bonding the valence electrons of the metal atoms become delocalized and enters into a sea of mobile electrons.

Question 11

How do these metals exist and become somewhat stabilized?
(supplemental reading)

Answer 11

Metallic bonds are the force of attraction between positive metal ions and the valence electrons that are constantly moving around them. The ions form a lattice-like structure held together by the metallic bonds. Metallic bonds explain why metals can conduct electricity and bend without breaking.

Question 12

What holds the cations into place?

Answer 12

The delocalized sea of electrons

Question 13

What is responsible for the observes properties of metals?

Answer 13

The electrostatic forces of attraction between the metal cations and the sea of electrons is responsible for the observed properties of metals
Example Mg- is a metal, is not stable and does not have a full valence shell

Question 14

What are the properties of metals? and why

Answer 14

1) High melting/boiling points-
because of the strong electrostatic forces between the cations and the sea of mobile electrons.
n.b mercury is the only liquid metal

2) Metals are good conductors of electricity-
due to the movement of charged particles as the delocalized electrons are able to move when potential difference is applied
.
3) Metals are shiny-
Light hits the surface and is reflected rather than passing through as the atoms are stacked closely together.

Question 15

What are the properties of metals? and why (2)

Answer 15

4) Metals are good conductors of heat-
In the structure of the metal the cations are packed very closely together, thus heat can be quickly passed along via vibrations from the hotter sections to the colder sections. The delocalized electrons help with transferring the hear from one point to another.
5) Density-
hard, malleable & ductile
6) Shiny luster
7) High density
8) Sonorous- metals make a ringing sound when we strike them.

Question 16

Malleable

Answer 16

able to be bent/hammered into sheets

Question 17

Ductile

Answer 17

able to be drawn out into wires (atoms are able to slide past eachother when a force is applied)

Question 18

Density

Answer 18

Measure of how “heavy” the metal is or how close the atoms are to each other