3.

Draw the electron dot structures for the following atoms and ions. How do you know the number of additional electron dots needed to convert an atom like sulfur (S) to an anion like sulfide, S^2-? The charge on the ion tells the number of "extra" electrons that must be added to the neutral atom. The charge on sulfide is -2. This means the sulfur atom needs two more dots to complete the octet. The formation of cations requires the removal of electrons from the neutral atom to form the positive ion.

Answer:

fluoride ion F^1-----------------------------------------30%-------

hydroxide ion, OH^1---------------------

potassium ion, K⁺-------------------------------------

4.

Explain why all hydrogen containing compounds are not acids like HCl(aq).

What happens in a solution of a strong acid like HCl(aq) that makes the mixture acidic?

What happens when water and ethanol, CH₃CH₂OH, are mixed?

Answer: When water and HCl are mixed the HCl molecule breaks up or dissociates to release H⁺ and Cl^1- ions. The bond between the hydrogen and chloride is weaker than the attraction between water and the H⁺ and Cl^1- ions. The release of the H⁺ ions is what makes the mixture acidic.

When water H₂O and alcohol mix the molecules of alcohol remain intact. Most the most part the molecules do not break apart to form ions. The mixture is a uniform distribution of H₂O molecules and CH₃CH₂OH molecules. There are no H⁺ ions released. The solution is not acidic.

5.

What happens when NaOH(s) is dissolved in water? What ions are formed in the solution? Tell whether the solution is acidic or basic.

Answer:: The solid sodium hydroxide dissolves in water. The water molecules are "polar". They have a positive pole or end associated with the hydrogens and a negative end or pole associated with the oxygen end

.

Many water molecules have their positive end attracted to an hydroxide ion. This attraction is so great that the water molcules are able to pull the hydroxide ion out of the solid. This kind of process is repeated bewteen diferent water molecules and the sodium ion. A different group of water molecules pull a sodium ion out of the crystal. The process is repeated billions and billions of times until either the solid has completely dissolved or there are no more unassociated water molecules. In general terms people say sodium hydroxide dissolves to release sodium ions and hydroxide ions. The solution is basic.

6.

What is the octet rule? Tell how the octet rule relates to the subshells in an atom. Why do you suppose hydrogen does not follow the octet rule? Do the atoms in row three, Na through Cl, always follow the octet rule? Does sulfur follow the octet rule when it forms the sulfide anion, S^2-?

Answer: Atoms gain and lose electrons to form a rare gas electron shell population. This means an atom gains or loses electrons to complete nsnp set of subshells. Hydrogen cannot follow the octet rule because it has valence electrons in the n = 1 level which has a capacity for only 2 electrons. Generally the elements in row two follow the octet rule. The elements in row three such as sulfur in SF₆ can violate the octet rule because the d subshell can be used to accommodate more than an eight electrons. Yes, sulfur follows the octet rule when it forms the sulfide anion.

7.

Why is the charge on a chloride ion a minus one when the chlorine atom gains an electron to form the ion?

Answer: Chlorine is in group 7A. The chlorine atom has 7 valence electrons and has room for one electron in the "valence shell". The negative charge is -1 because the neutral atom has gained one additional electron to form the anion.