Unit 1 prep 1

1)All of the following elements can form positive ions , except.........

• a-sodium(₁₁Na)

• b-chlorine(₁₇Cl)

• c-magnesium(₁₂Mg)

• d-aluminium(₁₃Al)

2)The number of energy levels in sodium ion is .......the number of energy levels in its atom.

• a-less than

• b- more than

• c-equal to

• d-no correct answer

3)when an atom is changed into an ion ,the ......is changed.

• a-number of protons

• b-number of electrons

• c-number of neutrons

• d-mass number

4)During the chemical reaction,a magnesium atom(₁₂Mg)loses its outer electrons and changes into ......

• a-Mg⁺

• b-Mg ^-

• c-Mg⁺²

• d-Mg ^-2

5)In trivalent elements ,the outrmost energy level contains....... electrons.

• a-(5) or(3)

• b-(7) or(1)

• c-(6) or (3(

• d-(5)or(6)

6)The valency of copper in(Cu₂O) is ....

• a-monovalent

• b-divalent

• c-trivalent

• d-tetravalent

7)Which of the following is a trivalent atomic number?

• a-Hydroxide

• b-Sulphate

• c-Ammonium

• d-Phosphate

8)The bright magnesium ribbon changes into a white powder of .....when it burns in air.

• a-magnesium nitrite

• b-magnesium hydroxide

• c-magnesium oxide

• d-magnesium dioxide

9)If the molecule of carbon dioxide consists of one atom of carbon and two atoms of oxygen,Knowing that the mass of carbon 12,and that of oxygen 16 So the mass of two molecules of carbon dioxide equals....gm.

• a-22

• b-88

• c-44

• d-33

10)The gases that affect the nervous system and the eye are.....

• a-nitrogen oxides

• b-carbon oxides

• c-Sulphur oxides

• d-(a) and (b)