Learn more about the properties, composition, and structure of substances (elements and compounds) with these Chemistry questions and answers. This Test can be used by students preparing for Chemistry in JAMB, WAEC, NECO or Post UTME.
| Substitute | Meltig point / ºC | Boiling point / ºC |
| P | - 78 | -25 |
| Q | - 8 | 40 |
| R | - 6 | 150 |
| S | 44 | 280 |
Which of the substances is a liquid at room temperature and rapidly evaporates on exposure to air?
P
Q
R
S
Correct answer is B
Q has slightly lower boiling point which when expose to air may evaporate rapidly.
Electropositivity of elements across the periodic table normally
remains constant down the group
Increases across the period
decreases across the period
decreases down the group
Correct answer is C
Electropositivity is known to increase down groups and decrease across periods in the modern periodic table (i.e., electropositivity decreases from left to right and it increases from up to down).
period 4, p- block
period 3, p- block
period 4, d- block
period 3, d- block
Correct answer is A
Selenium is a chemical element with the symbol Se and atomic number 34. It is a non-metal
Which of the following statements about atoms of a metal is correct? They
readily accept electrons
are soft
are held together by covalent bond
are held together by a sea of electron cloud
Correct answer is D
Metals are effectively lots of positively charged ions with a cloud/sea of delocalised electrons. This means the electrons are free to move throughout the metal, and is also why metals can conduct electricity as the electrons can move. The more delocalised electrons a metal has, the stronger it will be held together.
alkaline
amphoteric
acidic
neutral
Correct answer is B
An amphoteric oxide is an oxide that can act as either an acid or base in a reaction to produce a salt and water.