1. which of the following metals oxidized by calcium ions? a- potassium b- zinc c- iron d- lead 2. the first electrochemical cell was invented by a- michael faraday b- alessandro volta c- james maxwell d- benjamin 3. why cant a lead storage battery be charged indefinitely? a- a direct current must pass through the cells b- the electrodes lose lead sulfate c- it is difficult to reverse the direction of current flow d- the electrolyte is too expensive 4. which electrode (anode or cathode) is designated as positive in an electrolytic cell? a- anode b- cathode c- both d- neither 5. what is the direction of electron flow in an electrolytic cell? a- from cathode to anode b- from anode to cathode c- in either direction d- there is no flow 6. what electrolyte can be used to electrolyze water? a-

1 A

2 B

3 B

4 A

5 B

6 D

7 D

8 B

4

explanation:

- calcium has greater affinity to bond with electron receptors than hydrogen does and hence, it has the ability to replace hydrogen in most of its compounds.

- lithium has 2 valence electrons in the product because it can make only 1 bond with hydrogen. beryllium has 4 valence electrons in the product because it can only make 2 bonds. it has fewer electrons than neon and can react with electron donors. each hydrogen has 2 valence electrons, the same as helium.

- the covalent bond formed between carbon and hydrogen is polar because carbon is more electronegative than hydrogen and it attracts the bonded electron pair closer to itself, thus giving hydrogen a partial positive charge.

- a hydrogen bond is a relatively weak bond that hydrogen atoms make with the electronegative atoms nitrogen, oxygen or fluorine.

so the best choice is a.) 2 calcium (ca) atoms