science

1.What is the relative charge of.. a.proton b.neutron c.electron

2.Why does an atom have no overall charge?

3. How is mass number of an atom calculated?

4. What is the atomic number?

5.What are isotopes?

6.How many electrons can be held in the

a.first shell?

b.shells after the first?

1a. +1 b. 0 c. -1

2. There are an equal number of protons and electrons so they cancel each other out.

3. protons+neutrons=atomic mass number

4.number of protons

5.Isotopes are atoms of the same element with the same atomic number but a different mass number i.e a different amount of neutrons.

6a.2

6b.8

Accomodation:

Near objects:

-Ciliary muscles become tight, suspensory ligaments relax, lens becomes short and fat

Distant objects:

-ciliary muscles relax, suspensory ligaments become tight, lens becomes long and thin

Information is passed across synapses: transmitter substance is released across synapse, transmitter binds with receptor molecules on next neurone so electrical impulse can be released.

Long sight ----->convex lens------>light focuses behind retina

short sight------>concave lens----->light focuses before retina

Sustainable development means improving our quality of life without damaging the quality of life of future generations

These are some of the effects of urbanisation:

• increased pollution
• increased energy consumption
• land no longer used for food production
• loss of natural habitats
• decline of rural towns and villages as people leave them to live in cities

The growth in the human population and the increase in the standard of living are putting strains on the global environment:

non-renewable energy resources, such as coal, oil and natural gas, are being used up rapidly, raw materials are being used up rapidly, more waste is being produced, more pollution is being caused