Part II Microscopic World I

Which of the following statements concerning ³⁹₁₉X atom is correct?

• A. It has 19 neutrons.

• B. It has 20 protons.

• C. X is found in Group I in the Periodic Table.

• D. X is a non-metal.

Element Y consists of two naturally occurring isotopes, ¹⁰Y and ¹¹Y, with relative abundances of 19.7% and 80.3% respectively. What is the relative atomic mass of Y?

• A. 10.4

• B. 10.6

• C. 10.8

• D. 11.0

The numbers of subatomic particles in species P and those in species Q are shown.

Which of the following statements concerning P and Q is correct?

• A. P is the anion of Q.

• B. Q is the anion of P.

• C. P is the cation of Q.

• D. Q is the cation of P.

The atomic number of element Z is 9. Which of the following elements has similar chemical properties as Z?

• A. Sodium

• B. Magnesium

• C. Silicon

• D. Chlorine

Which of the following substances has a giant covalent structure?

• A. Sulphur dioxide

• B. Silicon dioxide

• C. Caesium chloride

• D. Copper

Which of the following electron diagrams is correct?

(Only the outermost shell electrons are shown in the diagrams.)

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• 
• 
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The atomic numbers of elements X and Y are 7 and 17 respectively. Which of the following is the correct formula of the compound formed between X and Y?

• A. XY

• B. XY₂

• C. XY₃

• D. XY₄

Which of the following statements concerning zinc is correct?

• A. The relative atomic mass of zinc is 67.

• B. There are 30 neutrons in each zinc isotope.

• C. There are more electrons in⁶⁶₃₀Zn than ⁶⁴₃₀Zn.

• D. There are 30 electrons in ⁷⁰₃₀Zn.

Which of the following is the correct explanation for the low melting point of fluorine?

• A. There is only one bond pair of electrons in a fluorine molecule.

• B. The atoms in each fluorine molecule are bonded together by weak covalent bond.

• C. There are only two fluorine atoms in a fluorine molecule.

• D. Fluorine molecules are held together by weak van der Waals’ forces.

Which of the following pairs of species have the same electronic arrangement?

• A. Cl^–, F^–

• B. Ne, Na⁺

• C. Li, Be²⁺

• D. N^3–, Ar