Question

The isotope of an unknown element, X, has a mass number of 79. The most stable ion of this isotope has 36 electrons and has a 22 charge. Which of the following statements is(are) true? For the false statements, correct them. (A) This ion has more electrons than protons in the nucleus. (B) The isotope of X contains 38 protons. (C) The isotope of X contains 41 neutrons. (D) The identity of X is strontium, Sr.

Answer 1

Answer:

A) False

B) True

C) True

D) True

Explanation:

A) False. If the charge of the atom is +2 means that you have two protons more than number of electrons. If you have 36 electrons you must have 38 protons. Also, the electrons are not in the nucleus.

B) True. The isotope of X contains 38 protons, two more than the electron number.

C) True. The mass number is the number of protons + number of neutrons.

If the mass number is 79 and there are 38 protons you must have 41 neutrons.

D) True. You can now the identity of the atom with the number of protons that is the same than atomic number. The strontium, Sr, is the atom with 38 as atomic number.

I hope it helps!