(a) Define relative atomic mass.

(b) Write down the relative atomic mass of magnesium and hydrogen.

(a) Milk goes sour.

(b) A piece of an apple rots on the ground.

(c) Water is absorbed by a paper towel.

(d) A plant undergoes photosynthesis in the presence of sunlight and turns CO2 and water into sugar and oxygen.

(a) What is process A called?

(b) Is process B showing a physical or chemical change? Give a reason for your answer.

(c) Is energy absorbed or released during process B?

(d) Is process C showing a physical or chemical change? Give a reason for your answer.

(1) Draw one atom of beryllium, which has 4 electrons, 4 protons and 5 neutrons. Label all the sub-atomic particles and show their charges.

(2) State Dalton’s Atomic Theory.

(3) Complete the table for a sodium atom.

(4) Redraw and complete the following table.

(a) How many electron shells does this atom have?

(b) How many electrons are there in the first shell?

(c) How many electrons are there in the second shell?

(d) Can these shells accommodate any more electrons?