Question

327 chemistry prep b unit 2 test - chapter 4 directions: for the first section of the test you will record your answer on your scantron. read each question carefully and select the best answer for each question. be sure to clearly bubble in your answer and fully erase any mistakes/changes on your scantron. 1) no matter the isotope, two atoms of the same element will always have the same: a. same number of protons b. same mass number c. same atomic mass 2) this is the sum of protons and neutrons in an element or isotope: a. atomic mass b. nuclear mass c. mass number d. atomic number 3) the smallest part of matter and retains the properties of the element is known as the: a. atom b. nucleus c. proton d. wave 4) this englishman proposed an atomic theory that atoms cannot be subdivided and atoms from the same element are identical: a. aristotle b. democritus c. dalton d. bohr 5) the subatomic particles that are found orbiting outside the nucleus are a. protons & electrons b. neutrons & protons c. electrons 6) the atomic number of an element is also equal to the number of subatomic particles a. neutrons b. protons c. electrons 7) true (a) or false (b): isotopes are variations of elements with different number of neutrons. 8) the name of the atom comes from the greek word “atomos,” which means? a. small b. indivisible c. proton d. nucleus 9) the charge of a neutron is a. +1 b. -1 c. 0 10) given that the average atomic mass of chlorine found on the modern periodic table is 35.5 amu, which isotope of carbon (shown above) must be the most abundant? a. chlorine - 37 b. chlorine - 35 c. it cannot be determined 11) true (a) or false (b): you can always find the number of electrons for a neutral atom directly on the periodic table of elements. answer questions 12 - 15 using this isotope: $_{12}^{24}mg$ 12) what is the mass number of this isotope? a. 24 b. 12 c. 24.3 d. none of the above 13) what is the atomic number of this isotope? a. 24 b. 12 c. 24.3 d. none of the above 14) what is the name notation? a. manganese - 24.3 b. magnesium - 24 c. manganese - 12 d. magnesium - 12 15) which of the following is a different isotope of magnesium? a. $_{25}^{12}mg$ b. $_{12}^{24}mg$ c. $_{12}^{25}mg$ d. $_{13}^{25}mg$ use the model of the atom to answer questions 16 - 20, bubble the letter that matches the question: 16) which label represents where the electrons are located? 17) which label represents where the protons are located? 18) which label represents where the nucleus is located? 19) which label represents where the electron cloud is located? 20) which label represents where the neutrons are located?

Explanation:

1. Atoms of the same element have the same number of protons regardless of isotopes.
2. Mass number is the sum of protons and neutrons.
3. An atom is the smallest part of matter with element - like properties.
4. Dalton proposed the atomic theory of non - subdivisible atoms and identical atoms of the same element.
5. Electrons orbit outside the nucleus.
6. Atomic number equals the number of protons.
7. Isotopes have different neutron numbers.
8. "Atomos" means indivisible.
9. Neutrons have a charge of 0.
10. Chlorine - 35 is more abundant as the average atomic mass is closer to 35.
11. For a neutral atom, number of electrons = number of protons which is on the periodic table.
12. Mass number is the top number in isotope notation (24 for \(_{12}^{24}Mg\)).
13. Atomic number is the bottom number (12 for \(_{12}^{24}Mg\)).
14. \(_{12}^{24}Mg\) is Magnesium - 24.
15. Isotopes of an element have the same atomic number but different mass numbers (\(_{12}^{25}Mg\) is a different isotope of Mg).

16 - 20: Electrons are in the outer region, protons and neutrons in the nucleus, and electron cloud is the outer area where electrons are likely to be found.

Answer:

1. a. same number of protons
2. c. mass number
3. a. atom
4. c. Dalton
5. c. electrons
6. b. Protons
7. A. True
8. b. indivisible
9. c. 0
10. b. Chlorine - 35
11. A. True
12. a. 24
13. b. 12
14. b. Magnesium - 24
15. c. \(_{12}^{25}Mg\)
16. Answer depends on the model (usually outer - most points like A or B)
17. Answer depends on the model (usually in the center like E)
18. Answer depends on the model (usually in the center like E)
19. Answer depends on the model (usually outer region)
20. Answer depends on the model (usually in the center with protons like E)