Chemistry Regent - Aug 2016 Q31-40

 Which list of elements is arranged in order of increasing electronegativity? (1) (3)  (2)  (4) 

• Be, Mg, Ca 
• F, Cl, Br
• K, Ca, Sc
• Li, Na, K

The table gives the masses of two different subatomic particles found in an atom.
Which of the subatomic particles are each paired with their corresponding name?

• X, proton and Z, electron
• X, proton and Z, neutron
• X, neutron and Z, proton
• X, electron and Z, proton

Which electron configuration represents an excited state for an atom of calcium? 

• 2-8-7-1
• 2-8-7-2
• 2-8-7-3
• 2-8-8-2

 At STP, graphite and diamond are two solid forms of carbon. Which statement explains why these two forms of carbon differ in hardness?

• Graphite and diamond have different ionic radii.
• Graphite and diamond have different molecular structures. 
• Graphite is a metal, but diamond is a nonmetal.
• Graphite is a good conductor of electricity, but diamond is a poor conductor of electricity.

Which equation shows conservation of charge?

• Cu + Ag⁺ → Cu²⁺ + Ag
• Mg + Zn²⁺ → 2Mg²⁺ + Zn
• 2F₂ + Br^- → 2F^- + C
• 2I^- + Cl₂ → I₂ + 2Cl^-

What occurs when potassium reacts with chlorine to form potassium chloride? 

• Electrons are shared and the bonding is ionic.
• Electrons are shared and the bonding is covalent.
• Electrons are transferred and the bonding is ionic.
• Electrons are transferred and the bonding is covalent.

Given the balanced equation representing a reaction:
H₂ + energy → H + H
What occurs as bonds are broken in one mole of H₂ molecules during this reaction? 

• Energy is absorbed and one mole of unbonded hydrogen atoms is produced. 
• Energy is absorbed and two moles of unbonded hydrogen atoms are produced.
• Energy is released and one mole of unbonded hydrogen atoms is produced.
• Energy is released and two moles of unbonded hydrogen atoms are produced. 

Which pair of atoms has the most polar bond? 

• H−Br
• I−Br
• H−Cl
• I−Cl

Which two notations represent isotopes of the same element?

• 1
• 2
• 3
• 4

The graph below shows the volume and the mass of four different substances at STP.
Which of the four substances has the lowest density?

• A
• B
• C
• D