Identify the missing information for each atom or ion. Note that the atoms and i
ID: 715173 • Letter: I
Question
Identify the missing information for each atom or ion. Note that the atoms and ions are not necessarily neutral.
A Se ion has a mass number of 78 and a charge of 2 . Determine the number of neutrons, protons, and electrons in this ion.
number of neutrons:
number of protons:
number of electrons:
An ion has a mass number of 65, 36 neutrons, and a charge of +1 . Identify the element symbol, and determine the number of protons and electrons in this ion.
element symbol:
number of protons:
number of electrons:
An atom or ion has 42 neutrons , 36 protons, and 36 electrons. Identify the element symbol, and determine the mass number and charge for this atom or ion.
element symbol:
mass number:
charge:
Explanation / Answer
Q1)
Atomic Number of Se = 34 = number of protons
number of electrons = number of protons + 2 = 34 + 2 = 36
Mass Number = Number of protons + number of neutrons
Number of neutrons = 78 - 34 = 44
Q2)
Number of Protons + Number of neutrons = Mass numbers
Number of protons = 65 - 36 = 29
Number of electrons = Number of protons - 1 = 29 - 1 = 28
Element is Cu (Copper)
Q3)
The element in Krypton (Kr)
Mass number = number of protons + number of neutrons = 42 + 35 = 78
Charge = 0 [since number of protons is equal to number of electrons]