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 indicates the number of protons in its nucleus. The mass number of 7 represents the total number of protons and neutrons in the nucleus. Therefore, the correct number of protons is 3. To find the number of neutrons, we subtract the atomic number from the mass number, which gives us 7 - 3 = 4. Lastly, since atoms are electrically neutral, the number of electrons is equal to the number of protons, so it is also 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 indicates the number of protons in its nucleus. Since the number of protons is equal to the number of electrons in a neutral atom, the correct number of electrons is also 12. The mass number of magnesium is 24, which is the sum of protons and neutrons. Therefore, the correct number of neutrons is 24 - 12 = 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 corresponds to the number of protons in its nucleus. The mass number of 65 represents the sum of protons and neutrons in the nucleus. Therefore, to find the number of neutrons, we subtract the atomic number from the mass number: 65 - 30 = 35 neutrons. Since atoms are electrically neutral, the number of electrons is equal to the number of protons. Thus, the correct number of protons, neutrons, and electrons for zinc is 30, 35, 30, respectively.
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. Since the atomic number of Bromine is 35 and it has 45 neutrons, the mass number can be calculated by adding the number of protons (35) and the number of neutrons (45), which equals 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 mass number of an atom is the sum of its protons and neutrons. Since aluminum has an atomic number of 13 (which indicates the number of protons in its nucleus) and 14 neutrons, we can calculate its mass number by adding these two values together: 13 + 14 = 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 represents the number of protons in its nucleus. Since the question states that Uranium has an atomic number of 92, it means that it has 92 protons. The number of neutrons is not relevant to determining the number of protons. Therefore, the correct answer is 92.
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 sum of protons and neutrons. Therefore, subtracting the atomic number from the mass number gives the number of neutrons, which is 12. Since sodium is a neutral atom, the number of electrons is equal to the number of protons, which is 11.
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. Since the atomic mass is the sum of the protons and neutrons in an atom, and it is given that there are 15 neutrons, we can conclude that the number of protons in Phosphorus is also 15.
9.
If carbon has an atomic mass of 12 and 6 neutrons, how many protons and electrons do it have, respectively?
Correct Answer
A. 6,6
Explanation
Carbon has an atomic number of 6, which means it has 6 protons. Protons have a positive charge, and electrons have a negative charge. In a neutral atom, the number of protons is equal to the number of electrons. Therefore, carbon also has 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 an atomic number of 19, which represents the number of protons in its nucleus. The atomic mass is determined by the sum of protons and neutrons in an atom. In this case, since Potassium has 19 protons and 20 neutrons, the atomic mass is 39.