Question

A student saw the following nuclear symbol for an unknown element: \({ }_{11}^{23} \mathrm{X}\). Which of the following statements about \(\mathrm{X}\) and \({ }_{11}^{23} \mathrm{X}\) are true? (a) \(\mathrm{X}\) is sodium. (b) \(\mathrm{X}\) is vanadium. (c) X has 23 neutrons in its nucleus. (d) \(\mathrm{X}^{2+}\) has 13 electrons. (e) \({ }_{11}^{23} \mathrm{X}\) has a proton/neutron ratio of about 1.1 .

Short answer

a) X is sodium b) X is vanadium c) X has 23 neutrons d) X²⁺ ion has 11 electrons e) The proton/neutron ratio of X is 1.1 Answer: a) X is sodium.

Step-by-step solution

Identify the element

According to the periodic table, an atomic number of 11 corresponds to sodium (Na). So, X = Sodium.

Verify statement (a)

Since X is sodium, statement (a) is true.

Verify statement (b)

Since X is sodium and not vanadium, statement (b) is false.

Calculate the number of neutrons

Knowing that the mass number (A) is 23 and that sodium has 11 protons, we can determine the number of neutrons by subtracting the number of protons from the mass number: 23 - 11 = 12 neutrons.

Verify statement (c)

Since X has 12 neutrons and not 23, statement (c) is false.

Determine X²⁺ ion's electron count

A neutral sodium atom has 11 electrons (equal to the atomic number). Since X²⁺ is an ion with a charge of +2, it means it has lost 2 electrons: 11 - 2 = 9 electrons.

Verify statement (d)

Considering that X²⁺ ion has 9 electrons, statement (d) is false.

Calculate proton/neutron ratio

Given that sodium has 11 protons and 12 neutrons, we can calculate the proton/neutron ratio by dividing the number of protons by the number of neutrons: 11/12 ≈ 0.917.

Verify statement (e)

Since the proton/neutron ratio of X is approximately 0.917 and not 1.1, statement (e) is false. In conclusion, the only true statement among the given options is statement (a): X is sodium.