Which species contains the same number of electrons and neutrons?A.11 HB.21 H −C.73 Li+D.3517 Cl−Page 10 of 77

The number of electrons in a neutral atom is equal to the number of protons. The number of neutrons can be found by subtracting the atomic number from the atomic mass number.

A. 1H (Hydrogen-1) has 1 proton, 1 electron, and 0 neutrons.

B. 2H- (Deuterium with a negative charge) has 1 proton, 2 electrons (1 extra due to the negative charge), and 1 neutron.

C. 7Li+ (Lithium-7 with a positive charge) has 3 protons, 2 electrons (1 less due to the positive charge), and 4 neutrons.

D. 35Cl- (Chlorine-35 with a negative charge) has 17 protons, 18 electrons (1 extra due to the negative charge), and 18 neutrons.

So, the species that contains the same number of electrons and neutrons is D. 35Cl-.