1.
If lithium has an atomic number of 3 and a mass number of 7, the correct number of protons, neutrons, and electrons, respectively, is:
Correct Answer
A. 3,4,3
Explanation
Lithium has an atomic number of 3, which represents the number of protons in its nucleus. The mass number of 7 indicates the total number of protons and neutrons in the nucleus. Therefore, since the atomic number is 3, there are 3 protons. Since the mass number is 7 and there are 3 protons, the number of neutrons can be calculated by subtracting the number of protons from the mass number, which gives us 7 - 3 = 4 neutrons. Finally, since atoms are electrically neutral, the number of electrons is equal to the number of protons, which is 3.
2.
If Magnesium has an atomic number of 12 and a mass number of 24, the correct number of protons, neutrons, and electrons, respectively, is:
Correct Answer
B. 12,12,12
Explanation
Magnesium has an atomic number of 12, which represents the number of protons in its nucleus. Since atoms are electrically neutral, the number of protons is also equal to the number of electrons. Therefore, the correct number of protons and electrons is 12. The mass number of magnesium is 24, which represents the total number of protons and neutrons in the nucleus. Since the number of protons is 12, the correct number of neutrons is also 12. Hence, the correct answer is 12,12,12.
3.
If Zinc has an atomic number of 30 and a mass number of 65, the correct number of protons, neutrons, and electrons, respectively, is:
Correct Answer
B. 30,35,30
Explanation
Zinc has an atomic number of 30, which represents the number of protons in its nucleus. The mass number of 65 indicates the total number of protons and neutrons in the nucleus. Therefore, the correct number of protons is 30. Since the atomic number also represents the number of electrons in a neutral atom, the correct number of electrons is also 30. To find the number of neutrons, we subtract the number of protons from the mass number, giving us 65 - 30 = 35 neutrons. Therefore, the correct answer is 30, 35, 30.
4.
If Bromine has an atomic number of 35 and has 45 neutrons, what is its mass number?
Correct Answer
D. 80
Explanation
The mass number of an atom is the sum of its protons and neutrons. In this case, the atomic number of Bromine is given as 35, which represents the number of protons in its nucleus. The question also states that Bromine has 45 neutrons. To find the mass number, we simply add the number of protons and neutrons together: 35 (protons) + 45 (neutrons) = 80. Therefore, the mass number of Bromine is 80.
5.
If Aluminum has an atomic number of 13 and has 14 neutrons, what is its mass number?
Correct Answer
B. 27
Explanation
The atomic number of an element represents the number of protons in its nucleus, which in this case is 13 for aluminum. The mass number of an element is the sum of its protons and neutrons. Since it is given that aluminum has 14 neutrons, we can calculate its mass number by adding the number of protons (13) and neutrons (14), which gives us a total of 27.
6.
If Uranium's atomic number is 92 and it has 10 neutrons, how many protons does it have?
Correct Answer
B. 92
Explanation
Uranium's atomic number corresponds to the number of protons in its nucleus. Since the atomic number is given as 92, it means that uranium has 92 protons. The number of neutrons is not relevant to determining the number of protons in an atom.
7.
If Sodium has an atomic number of 11 and a mass number of 23, how many protons, neutrons, and electrons does it have, respectively?
Correct Answer
C. 11,12,11
Explanation
Sodium has an atomic number of 11, which represents the number of protons in its nucleus. The mass number of 23 indicates the total number of protons and neutrons in the nucleus. Therefore, the number of neutrons can be calculated by subtracting the atomic number from the mass number. Finally, since atoms are neutral, the number of electrons is equal to the number of protons. So, the correct answer is 11 protons, 12 neutrons, and 11 electrons.
8.
If Phosphorus has an atomic mass of 30 and 15 neutrons, how many protons does it has?
Correct Answer
A. 15
Explanation
Phosphorus has an atomic mass of 30 and 15 neutrons. The atomic mass of an element is the sum of the number of protons and neutrons in its nucleus. Since the atomic mass is given as 30 and there are 15 neutrons, the number of protons must be equal to the atomic mass minus the number of neutrons, which is 30 - 15 = 15. Therefore, Phosphorus has 15 protons.
9.
If carbon has an atomic mass of 12 and 6 neutrons, how many protons and electrons does it have, respectively?
Correct Answer
A. 6,6
Explanation
Carbon has an atomic number of 6, which indicates the number of protons in its nucleus. Since the number of protons and electrons in an atom are equal, carbon also has 6 electrons. The number of neutrons is not mentioned in the question, so we cannot determine it. Therefore, the correct answer is 6 protons and 6 electrons.
10.
If Potassium has 19 protons, 19 electrons, and 20 neutrons, what is its atomic mass?
Correct Answer
C. 39
Explanation
Potassium has 19 protons and 20 neutrons, so the atomic mass is the sum of these two numbers, which is 39. The number of electrons does not contribute to the atomic mass because their mass is negligible compared to protons and neutrons.