Question

which pair have approximately the same mass?
a a hydrogen, 1^h, and a deuterium, 2^h, atom
b a proton and a neutron
c a neutron and an electron
d an electron and a proton
question 25 (1 point)
how many protons, electrons, and neutrons, respectively, does 27 al 3+ have?
a 13, 13, 27
b 13, 10, 14
c 13, 13, 13
d 13, 13, 14
e 13, 10, 27

Explanation:

First Question (Which pair have approximately the same mass?):

• Option a: Hydrogen ($^1$H) has 1 proton (mass ~1 amu), deuterium ($^2$H) has 1 proton + 1 neutron (mass ~2 amu) – masses differ.
• Option b: Proton mass ≈ 1.007 amu, neutron mass ≈ 1.008 amu – approximately same.
• Option c: Neutron mass ~1 amu, electron mass ~0.0005 amu – differ greatly.
• Option d: Electron mass ~0.0005 amu, proton ~1 amu – differ greatly.

Step1: Find protons (atomic number of Al)

Aluminum (Al) has atomic number 13, so protons = 13.

Step2: Find electrons (ion charge)

$^{27}\text{Al}^{3+}$ is a 3+ ion, so electrons = protons - charge = $13 - 3 = 10$.

Step3: Find neutrons (mass number - atomic number)

Mass number = 27, atomic number = 13, so neutrons = $27 - 13 = 14$.

Answer:

b. a proton and a neutron

Second Question (How many protons, electrons, and neutrons in $^{27}\text{Al}^{3+}$?):