Answer:
a) 
b) 
c) 
d) 
Explanation:
For neutral atoms:
Atomic Number (Z)= number of protons = number of electrons
Mass number (A) = number of protons + number of neutrons
For ions with positive net charge:
Number of protons = Z + net charge
For ions with negative net charge:
Number of protons= Z - net charge
a) A = 71, Charge = +3
Number of electrons = 28
Number of protons = 28 +3 =31

b) A = 35, Z = 45+35=80, Charge = -1
Number of protons =35
Number of neutrons = 45
Number of electrons = 36
Charge = Number of protons- Number of electrons =35-36 = -1

c) Charge = +4
Number of electrons = 86
Number of protons = Z = 86+4 = 90
mass number = A = 90+142 = 232

d) Charge = +2
Atomic number = Number of protons = Z = 38
mass number = A = 87

Answer:
Explanation:
I’m 99.9% sure that it’s an element because it can’t be broken down any more than it already is.
Answer:
C
Explanation:
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When a monovalent cation X binds to a divalent anion Y, a compound with the formula
would be formed.
A monovalent cation is an atom that has lost an electron. Hence, such cation has a single positive charge. A monovalent cation X will, thus, be 
A divalent anion is an atom that has gained two electrons. Such anion has 2 negative charge. Thus, divalent Y would be 
Since Y is a divalent anion, it requires 2 electrons in order to successfully bind with another charged atom, a cation to be specific. Thus, two of
would be required to successfully bind 
+
+
---->
More on the chemical formula can be found here: brainly.com/question/16741890