Question

1. does element a or element b have a higher electronegativity?

a. element a because it is smaller and holds electrons more tightly.
b. element b because it is larger and holds electrons more tightly.
c. element a because it is a nonmetal and wants to gain electrons.
d. element b because it is a metal and wants to gain electrons.

1. which element would have the following lewis dot diagram?

a. chlorine
b. helium
c. lithium
d. phosphorous

1. how many valence electrons does an atom of carbon (c) have?

a. 1 b. 2 c. 4 d. 6

1. which of these are alkaline earth metals? cu, sr, cd, au, ca, be, co

a. sr, be, ca b. cu, cd, au, co c. cu, au, be, co d. all 7 elements

1. which elements would be in period 2? *note these models are not drawn to scale

a) a and d only b) c and e only c) b, c and e only d) none of these

1. refer to the elements in #15. which elements have the highest shielding effect?

a) a and d only b) c and e only c) b, c and e only

1. what is the oxidation number (charge) of fluorine?

a) -7 b) -3 c) -1 d) +7

1. which element would be the smallest?

a) oxygen b) sulfur c) selenium

1. which element has the lowest ionization energy?

a) ca b) ge c) se d) br

1. which element has the largest electronegativity?

a) mg b) sr c) ba d) be

Explanation:

1. Smaller atoms have higher electronegativity as they hold electrons more tightly. Element A is smaller, so it has higher electronegativity.
2. Chlorine has 7 valence electrons which is represented in the Lewis - dot diagram.
3. Carbon has an atomic number of 6, and its electron configuration is 1s²2s²2p², so it has 4 valence electrons.
4. Alkaline - earth metals are in Group 2 of the periodic table. Sr (strontium), Be (beryllium), and Ca (calcium) are in Group 2.
5. Elements in period 2 have 2 electron shells. A and D have 2 electron shells.
6. Elements with more electron shells have higher shielding effect. C and E have more electron shells among the given ones in #15.
7. Fluorine is highly electronegative and has an oxidation number of - 1 in most compounds.
8. Atomic size increases down a group. Oxygen is the smallest among oxygen, sulfur, and selenium as it is at the top of Group 16.
9. Ionization energy decreases down a group and increases across a period. Ca is in Group 2 and has the lowest ionization energy among Ca, Ge, Se, and Br.
10. Electronegativity decreases down a group. Be is at the top of Group 2 among Mg, Sr, Ba, and Be, so it has the largest electronegativity.

Answer:

1. a. Element A because it is smaller and holds electrons more tightly.
2. a. chlorine
3. c. 4
4. a. Sr, Be, Ca
5. a) A and D only
6. b) C and E only
7. c) - 1
8. A) oxygen
9. A) Ca
10. D) Be