Question

e. 18 Test Your Knowledge MULTIPLE CHOICE: Choose the one best answer. 1. Each element has its own characteristic atom in which a. the atomic mass is constant. b. the atomic number is constant. c. the mass number is constant. d. Two of the above are correct. e. All of the above are correct. 2. Which of the following is not a trace element in the human body? a. iodine b. zinc c. iron d. calcium e. fluorine 3. A sodium ion (Na) contains 10 electrons, 11 pro- tons, and 12 neutrons. What is the atomic number of sodium? c. 12 e. 33 b. 11 d. 23 4. Radioactive isotopes can be used in studies of met- abolic pathways because a. their half-life allows a researcher to time an experiment b. they are more reactive. c. the cell does not recognize the extra protons in the nucleus, so isotopes are readily used in metabolism. d. their location or quantity can be experimentally de- termined because of their radioactivity. e. their extra neutrons produce different colors that can be traced through the body. 5. Which of the following atomic numbers would describe the element that is least reactive? a. 1 c. 12 b. 8 d. 16 6. An atom of argon has three electron shells, all of which are full. Its atomic mass is 40. How many neutrons does it have? a. 8 c. 20 e. 24 b. 16 7. Which of the following describes what happens as a chlorophyll pigment absorbs energy from sunlight? a. An electron moves to a higher electron shell and the electron's potential energy increases b. An electron moves to a higher electron shell and its potential energy decreases c. An electron drops to a lower electron shell and re- leases its energy as heat. d. An electron drops to a lower electron shell and its potential energy increases. e. An electron of sunlight is transferred to chlorophyll, producing a chlorophyll ion with higher potential energy d. 22 a. 10

Answer 1

1. Each element has its own characteristic atom in which: b. the atomic number is constant

2. d. Calcium is not a trace element in the human body.

3. The number of protons denotes the atomic number of an element: Hence the answer is b. 11.

4. Radioactive isotopes can be used in studies of metabolic pathways because - d. Their location or quantity can be experimentally determined because of their radioactivity.

5. e. 18, will habe the electronic configuration 2, 8, 8. With the outermost shell having 8 electrons, it makes the element with atomic number 18 the least reactive element.

6. The number of neutrons in argon is d. 22

7. When chlorophyll pigment absorbs energy from sunlight - a. An electron moves to a higher electron shell and the electron's potential energy increases.

8. Number of electrons phosphorus has in its valence shell is b. 5.

9. Atomic mass of phosphorus is c. 31

10. The isotope of carbon with mass number 14 has an atomic number 14-6 = 8

11. The number of covalent bonds sulfur atom is most likely to form d. 4

12. Based on electronic configuration the element which would have chemical behaviour most like that of oxygen is e. S

13. C, N, O are found next to each other in Group II and S, P next to each other in Group III. Hence the correct answer is C.

14. A covalent bond between two atoms is likely to be nonpolar is

b. the two atoms are about equally electronegative.

c. the two atoms are of the same element.

Answer e both b and c.

15. A triple covalent bond would e. involve the sharing of six electrons.

16. A cation

c. is more likely to form in an atom with seven electrons in its valence shell

d. has a positive charge.

Answer is e. both c and d are correct.

17. b. polar covalent bond

18. d. Hydrogen bond

19. b. non-polar covalent bond

20. Potassium is expected to participate in

a. ionic; it would lose one electron and carry a positive charge.

21. a. nonpolar covalent bonds.

22. The molecular shape of methane is C. tetrahedral, with carbon in the center and H at each corner.

I have answered till 22.

KINDLY RATE IF THIS WAS HELPFUL TILL 22.