43
The stability of the noble gases is due to the fact that they?
- A. have no electron in their outermost shells
- B. have duplet or octet electron configurations
- C. belong to group zero of the periodic table
- D. are volatile in nature
44
How many unpaired electron(s) are there in the nitrogen sub-levels?
- A. 3
- B. 2
- C. 1
- D. none
45
Moving from left to right across a period, the general rise in the first ionization energy can be attributed to the?
- A. decrease in nuclear charge
- B. increase in nuclear charge
- C. decrease in screening effect
- D. increase in screening effect
46
The volume of a given gas is V cm3 P mm Hg. what is the new volume of the gas if the pressure is reduced to half at constant temperature?
- A. 4 V cm3
- B. 2 V cm3
- C. V/2 cm3
- D. V cm3
47
The droplets of water observed around a bottle of milk taken out of the refrigerator is due to the fact that the?
- A. water vapour in the air around the bottle gains some energy from the bottle
- B. temperature of the milk drops as it loses heat into the surroundings
- C. saturated vapour pressure of the milk is equal to the atmospheric pressure
- D. water vapour in the air around the bottle loses some of its energy to the bottle
48
Calculate the percentage by mass of nitrogen in calcium trioxonitrate (V)
[Ca = 40, N = 14, O = 16]
- A. 8.5%
- B. 13.1%
- C. 17.1%
- D. 27.6%
49
Which of the following is an example of a mixture?
- A. Common salt
- B. Blood
- C. Sand
- D. Washing soda