nakuru district secondary schools trial examination - KCSE Online

3. Identify (3marks)a) solution K…………………………………………………………………………………………b) Solid L……………………………………………………………………………………………c) Gas M……………………………………………………………………………………………4. An element in period 4 forms the oxide P 2 Oa) What is the valency of P (1mark)…………………………………...…………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………….......(b) What name is given to the group to which element P belongs(1mark)..................................................................................................................................................(c) Write down the electronic arrangement of P in the oxide P 2 O (1mark)…………………………………...…………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………….......5 Distinguish between nuclear fission and nuclear fusion (2marks)…………………………………...…………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………….......6 K grammes of a radio active isotope decayed to 6.5g in 100 days. The half-life of the isotopeis 25 days.(a) What is meant by half-life(1mark)......................................................................................................................................................(b) Calculate the initial mass of isotope K(2marks)…………………………………...……………………………………………………………Visit:3www.kcse-online.info for thousands of free Past papers