An atom has 18 protons, 18 electrons, and 20 neutrons. This atom has _____. A) a negative charge B)an atomic number of 20 C)a mass number of 38 D) a positive charge Which one of these is the answer?
2 Answers
C.
Explanation:
as no. of protons is equals to the no. of electrons so, it is a neutral atom.
but, as Atomic No. = Mass No. - No. of neutrons
Atomic No. = No. of protons = 18
so, Mass No. = Atomic No. + No. of Neutrons= 18 + 20 = 38
so, correct option is C.
Answer is
Explanation:
A) Incorrect. Because the number of electron of the atom is 18 which means its electron arrangement is 2.8.8. This show that it has reached stable octet arrangement and will not receive or donate any electrons to form ion.
B) Incorrect. Because the atomic number of an atom is same as the proton number of the atoms which means the atomic mass of the atom equal to 18.
C) Correct. Because the mass number of an atom is the sum of proton number and neutron number of the atom. So, 18 + 20 = 38.
D) Incorrect. Explanation is same as A.
