Chemistry

24– Mass number (Protons + Neutrons)
Mg
      12– Atomic number (Protons + Electrons)

                                         Relative mass                                     Charge

Proton                                     1                                                       +1

Neutron                                   1                                                        0

Electron                            Very small                                               -1

Atoms are neutral because they have equal number of Protons and electrons so cancel each ther out.

Isotopes
It is an copy of an atom,same number of Protons/electrons but not neutrons.

12 13
C C                   Reaction same because same number of electrons. Carbon 13
6 6                    Will be heavier because it has more neutrons which control mass.
P=6 P=6
E=6 E=6
N=6 N=7

➖1 electron in outer shell

➖Called alkali metals because very reactive

➖React rapidly with oxygen, chlorine and water

As you go down it gets more reactive because......

➖ Outer electron is further from nucleus so less attraction and easier to lose.

➖Full electrons in outer shell

➖Stable because electrons don’t need to be gained or lost

➖Very unreactive as full electrons in outer shell

As you go down..

➖ Boiling point increases as relative atomic masses increase

➖ Intermolecular force increases because atoms get bigger which is why force hard to separate

➖Very unreactive because no electrons moving as full outer shell so no reactions take place

➖7 electrons in outer shell

➖From molecules when when two atoms join by covelent bonds

➖From covenant compounds when they react with other non-metal atoms

As you go down it gets less reactive because..

➖Outer shell further from nucleus so less attraction and electron harder to gain

➖Melting and boiling points increase

➖Molecules get bigger

- When metal and non-metal transfer electrons to become ions

Properties of ionic bonding:

- Giant ionic latitice

- High melting and boiling points so ionic bonds are very strong and lots of energy needed to break them

- Solid ionic compounds don't conduct electricity because no free ions

- Dissolved or melted ionic compounds conduct electricity because ions free to move

Positive ions, surrounded by delocalised electrons

- Electrostatic attrcation is attraction between positive object and negative object

- Strong electrostatic attraction between sea of delocalised electrons and positive metal ions

Properties of  metallic bonding:

- Giant metallic lattice

- High melting and boiling points so metallic bonds are strong and lots of energy needed to break bonds

- Conducts electricity and heat beacsue free ions. Also electrons carry thermal energy to let metals conduct heat

- Mallebale is shaping ions. When force is applied ions move - Ductile is drawn into wires. When you stretch it, it forms a wire. - In metals layers of atoms are able to slide over each other

- Takes place between non-metal elements

- Shaired pair of electrons

- Electroststic attrcation makes covelent bonds very strong

Substances containg covelant bonds have simple molecualr structures:

-The atoms in molecules are held by covelent bonds

-Low melting and boiling points, so gases and liquids

- Don't conduct electricity as no free ions

- Weak intermolecular force between molecules so don't need alot of energy to break

- Always solid at room temperature because they have millions of covelent bonds so high melting and boiling point

Diamond

- Formed from carbon, makes four covelent bonds

- Has loads of covelent bonds which have to be broken when diamond is melted which requires loads of energy. Cannot conduct electricty as no free electrons

Silicon dioxide

-High metling and boiling point because loads of covelent bonds that requires lots of energy to be broken

Graphite                                                                                                                           Makes 3 covelent bonds. HIgh melting and boiling point as many covelent bonds so lots of energy needed to break bonds. Soft and slippery as no covelent bonds between layers so can slide. Conducts heat and electricity because delocalised electrons that can move.

Graphene

-Single layer of graphite,one atom thick. Very strong. Conductor of electricity because delocalised electrons can move. Used in electronics

Fullerenes

-Molecules of carbon atoms with hollow shapes. Hexagonal rings,five or six carbon atoms. Used to deliver drugs into body, for lubricants like machines stopping parts grinding together and catalysts which is to speed up reactiona

Carbon nanotubes

Shaped into long cylinders, rings form 6 carbon atoms, high tesile strength (stretched without breaking) Conductors of heat and electricity