What is a compound?

• When two elements react with each other.

• A molecule made up of different elements.

• A substance made of two or more elements that are chemically joined together.

Which electrons in an atom are involved in bonding?

• The Inner electrons (closest to nucleus).

• The outer electrons (highest energy level of shells).

• All electrons.

What happens to the electrons in atoms when ionic bonds are formed?

• They are lost in the reaction.

• They are shared with the other atom - so all atoms have full shells.

• They are transferred (metal lose electron, non-metal gains electron)

What happens to electrons in atoms when covalent bonds are formed?

• They are shared (for each covalent bond, a pair of electrons is shared)

• They are transferred (metal atom loses electron, non-metal atom gains electron)

• Outer electrons are lost in reaction.

Why do the elements in group 1 form ions with a single positive charge?

• They gain an electron, which means its charge becomes positive.

• They lose one outer electron (which has a negative charge, so charge becomes positive)

• They gain protons in it's nucleus so its charge becomes positive.

Why do elements in group 7 form ions with a single negative charge?

• They lose their seven electrons which makes the atom charge negative.

• They lose one electron which makes the atom negative.

• They gain one electron to make a full outer shell (electron is negative).

Why can the structure of a metallic element like copper be represented by lots of spheres the same size packed closely together?

• The atoms in copper are all the same size (and are spherical) and are packed tightly together (as a solid, in a giant structure)

• Atoms are always represented as small circles the same size, solids are made of closely packed atoms and copper is a solid (at room temp).

• Atoms are all metallic so are the same size and are packed closely together (as they attract each other).

Why do ionic compounds have giant structures?

• Ions always have a free bond so attract more and more ions.

• The forces between oppositely charged ions act in all directions, so ions are packed closely together in a regular arrangement.

• Ions are very small so a crystal contains many ions.

Which is the correct dot and cross diagram for CH4? (4 is subscript)

Which is the correct diagram showing covalent bonds for H2O and 02?

• H-O-H, O=O

• H-O-H, O-O

• H-H-O, O=O

Why does silicon (group 4) have a giant structure?

• Group for elements can react and join to multiple atoms, this happens here and a giant structure is formed.

• Silicon atoms join to others in al directions, so giant structure is formed.

• They have four covalent bonds, so form to four other atoms, this continues until a giant structure is formed.

How are the atoms in sodium (metal) held together?

• Atoms share electrons with each so all atoms have a full outer shell, this holds the atoms in place together. (forces between atoms are strong)

• Outer electrons delocalise, leaving a lattice of positive ions, the delocalised electrons attract positive ions and hold them in position. (Electrostatic forces are strong)

• Metallic atoms attract each other and are held together by strong magnetic forces.