UP 2

Prepared By, Cikgu Sathish 1

1 EXERCISE 1. Table below shows the proton numbers and neutron numbers of a few elements which are

represented by the letters U,V,W,X,Y and Z.

Element Number of Proton

per atom Number of Neutron

per atom Electron

Arrangement U 3 4 V 5 6 W 8 8 X 9 10 Y 12 12 Z 17 20

a) Complete table by writing the electron arrangements of all the particles. b) What is the nucleon number of U? c) What is the number of valence electrons in ion U+? d) State the number of electron shells in particle Y. e) Draw the electron arrangements of particle Z and ion W2-, respectively.

2. a) What is meant by isotope? b) Chlorine-35 and chlorine-37 is a pair of isotopes.

i) State two similarities between these isotopes. ii) State the difference between these isotopes.

c) Hydrogen has three isotopes. i) Name the three isotopes of hydrogen. ii) Give the symbols of the isotopes named in c(i).

d) Table below shows the isotopes and their uses in daily life. Complete Table below. Isotopes Use of Isotopes in Daily Life

Cobolt-60 i)

ii) To detect clotting of blood in body

iii) To determine the rate of absorption of fertilizers by the plants

UP 2

Prepared By, Cikgu Sathish 2

1 3. Aspartame is an artificial sweetener that has no calorie. Its molecular formula is

C14H18N2O5. Calculate its relative molecular mass. [Ar: H=1; C=12; N=14; O=16]

4. 5.5 g of gas Y occupies a volume 3 dm3 at room temperature. Find the relative molecular mass of gas Y. [1 mole of gas occupies a volume 24 dm3 at room temperature]

5. Magnesium can burn in oxygen to produce magnesium oxide. a) Write the chemical equation showing the reaction. b) Calculate the mass of magnesium oxide that formed if 4.8g of magnesium is

burnt. c) Calculate the volume of oxygen needed for the combustion of 3g of magnesium at

room temparature. [Ar: O= 16; Mg= 24. 1 mole of gas occupies a volume 24 dm3 at room temperature]