Question

select the subatomic composition of a zirconium - 90 atom. refer to a periodic table. 40 protons, 50 neutrons, 40 electrons 50 protons, 40 neutrons, 50 electrons 40 protons, 40 neutrons, 40 electrons 50 protons, 50 neutrons, 50 electrons

Explanation:

Step1: Find atomic number of zirconium

From periodic - table, atomic number of zirconium (Zr) is 40. Atomic number = number of protons = number of electrons in a neutral atom. So, number of protons = 40 and number of electrons = 40.

Step2: Calculate number of neutrons

Mass number = number of protons+number of neutrons. Given mass number of zirconium - 90 is 90. So, number of neutrons = mass number - number of protons = 90 - 40=50.

Answer:

40 protons, 50 neutrons, 40 electrons