Question

question 4 (2 points)
(03.03 mc)
what happens when the compound hcl is formed?
o a hydrogen transfers two electrons to chlorine.
o b hydrogen receives two electrons from chlorine.
o c hydrogen forms an ion with -1 charge; chlorine forms an ion with +1 charge.
o d hydrogen forms an ion with +1 charge, chlorine forms an ion with -1 charge.

question 5 (2 points)
(03.03 mc)
what is the formula unit for a compound made from ca and o?
o a cao₂ because the total negative charge on o is two.
o b ca₂o because the total negative charge on ca is one.
o c cao because the total positive charge on o is one.
o d cao because the total positive charge on ca is two.

question 6 (2 points)
(03.03 lc)
the lewis dot notation for two atoms is shown.

what is represented by this notation?
o a mg gains two protons from o.
o b mg donates two protons to o.
o c mg gains two electrons from o.
o d mg donates two electrons to o.

Explanation:

• Question 4:
• Hydrogen has one valence electron and chlorine has seven valence electrons. In the formation of \(HCl\), hydrogen loses one electron (forms \(H^{+}\) with a \(+ 1\) charge) and chlorine gains one electron (forms \(Cl^{-}\) with a \(-1\) charge).
• Option a: Hydrogen has only one electron to transfer, not two.
• Option b: Hydrogen loses, not receives electrons in this ionic - like (it's actually a polar covalent but in terms of electron - transfer concept for simplicity here) interaction.
• Option c: The charges are reversed.
• Question 5:
• Calcium (\(Ca\)) has a \(+2\) charge (\(Ca^{2+}\)) and oxygen (\(O\)) has a \(-2\) charge (\(O^{2 -}\)).
• For a neutral compound, the formula unit is \(CaO\) (the charges balance as \(+2+(-2) = 0\)).
• Option a: \(CaO_{2}\) would have a net charge of \(+2+2\times(-2)=-2\).
• Option b: \(Ca_{2}O\) would have a net charge of \(2\times(+2)+(-2)= + 2\).
• Option c: Oxygen has a negative charge, not a positive charge.
• Question 6:
• In Lewis dot notation for ionic bonding (as in the case of \(MgO\) which is an ionic compound), magnesium (\(Mg\)) has two valence electrons.
• Magnesium donates its two valence electrons to oxygen (which needs two electrons to complete its octet). Protons are in the nucleus and are not transferred in chemical bonding (only electrons are transferred in ionic bonding).

Answer:

• Question 4: d. Hydrogen forms an ion with +1 charge, chlorine forms an ion with -1 charge.
• Question 5: d. \(CaO\) because the total positive charge on \(Ca\) is two.
• Question 6: d. \(Mg\) donates two electrons to \(O\).