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.
Which of the following statements is NOT true of electrovalent compounds?
They are solids
They do not vaporized easily
They usually dissolve in water
The elements forming the compounds normally have their valency electrons in a shared state
They conduct electricity
Correct answer is D
No explanation has been provided for this answer.
The number of atoms in one mole of a substance is equal to?
the atomic number
the avogadro number
the gas constant
the number of neutrons
the number of electrons
Correct answer is B
Avogadro's number is defined as the number of elementary particles (molecules, atoms, compounds, etc.) per mole of a substance.
gain of electrons
loss of electrons
gain of hydrogen
loss of oxygen
addition of an electropositive element to a substance
Correct answer is B
Oxidation is the loss of electrons or an increase in the oxidation state of a chemical or atoms within it.
Sodium and potassium belong to the same group of the Periodic Table. This is because?
both are metals
both are soft and lighter than water
both form cations by losing electrons
both have identical electronic configuration
both react with water vigorously
Correct answer is C
They react easily because they lose their 1 valence electron easily to gain their stable octet configuration. Hence, they form the +1 cation easily.
The mass number of an atom is?
the number of electrons in the atom
the number of protons in the nucleus of the atom
the number of neutrons in the nucleus of the atom
the sum of numbers of electrons and protons inthe atom
the sum of numbers of proton and neutrons in the nucleus of the atom
Correct answer is E
No explanation has been provided for this answer.