Question

unit 2 - electrons and periodic table test
part 1 - multiple choice: select the letter that best answers the question and record on your answer sheet.

1. the bohr model for a neutral atom of this element will have 2 energy levels and 4 valence electrons:

a. calcium b. carbon c. barium d. beryllium

1. an element is found in period 3, group 17. its bohr model will have __ energy levels and __ valence electrons.

a. 3, 17 b. 3, 7 c. 3, 35 d. 7, 35

1. which element will not have a lewis dot structure that looks like element x to the right?

a. nitrogen b. boron c. antimony d. bismuth

1. typically when neutral atoms form ions, it is to obtain an octet. how many valence electrons will this be?

a. 1 b. 4 c. 12 d. 8

1. which element will not form an anion?

a. oxygen b. chlorine c. magnesium d. nitrogen

1. the arrows on the periodic table to the right show the direction of the trend increasing. which of the following periodic trends follows the pattern shown?

a. ionization energy b. electronegativity c. atomic radius d. both a and b e. all of the above

1. which of the following groups of elements would most likely have the greatest electronegativity?

a. group 17 b. group 1 c. group 2 d. transition metals

1. which of the following elements has the greatest atomic radius?

a. rb b. s c. na d. fr

1. which of the following elements has the smallest ionization energy?

a. cl b. be c. mg d. ba

1. nonmetals have __ electronegativities and thus form a __ charge as they lose electrons.

a. low; negative b. high; negative c. low; positive d. high; positive

1. identify the element with the following electron configuration: 1s²2s²2p⁶3s²3p⁴.

a. o b. s c. cr d. si

1. which electron configuration below represents an element that is a metal?

a. 1s¹ b. 1s² 2s² 2p³ c. 1s² 2s² 2p⁶ 3s¹ d. 1s² 2s²

1. identify the number of valence electrons in an element with this electron configuration: 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p¹.

a. 1 b. 3 c. 13 d. 31

1. which noble gas should be used in the noble gas abbreviated electron configuration for bromine?

a. he b. ne c. ar d. kr

Explanation:

1. Carbon has 2 energy - levels and 4 valence electrons in its Bohr model.
2. An element in Period 3 has 3 energy - levels and Group 17 elements have 7 valence electrons.
3. Boron has a different number of valence electrons compared to the element shown by the Lewis - dot structure.
4. An octet is 8 valence electrons.
5. Magnesium is a metal and forms cations, not anions.
6. Ionization energy and electronegativity increase across a period and up a group.
7. Group 17 elements have high electronegativity.
8. Francium has the largest atomic radius among the given elements as it is in the lowest period.
9. Barium has the smallest ionization energy as it is in the lowest period among the given elements.
10. Non - metals have high electronegativities and gain electrons to form negative charges.
11. The electron configuration $1s^{2}2s^{2}2p^{6}3s^{2}3p^{4}$ corresponds to sulfur.
12. The electron configuration $1s^{2}2s^{2}2p^{6}3s^{1}$ represents a metal (sodium).
13. For the electron configuration $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{1}$, the valence electrons are in the 4s and 4p orbitals, so there are 3 valence electrons.
14. Argon is used in the noble - gas abbreviated electron configuration for bromine.

Answer:

1. B. Carbon
2. B. 3, 7
3. B. Boron
4. D. 8
5. C. Magnesium
6. D. Both A and B
7. A. Group 17
8. D. Fr
9. D. Ba
10. B. high; negative
11. B. S
12. C. $1s^{2}2s^{2}2p^{6}3s^{1}$
13. B. 3
14. C. Ar