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

There is 6.02*10^23 molecule per mole. And there is 2 atoms per oxygen molecule. So the answer is 1.204*10^24 atoms in 1.0 mole of O2.
D only..
A is pure compound
B is mixture of compound and element
C is mixture of compounds
D is mixture of elements
Answer:
Because all farms cant afford it... im not sure if this is the answer your lookin for but if it aint lmk and ill delete my answer
Explanation:
Answer:
Heterogeneous mixture
Explanation:
A homogeneous mixture is defined as a mixture in which the constituents of the mixture are uniformly distributed. A typical example of a homogeneous mixture is when a salt is dissolved in water.
A heterogeneous mixture refers to a kind of mixture whereby the composition of the mixture is not uniform. A typically example of a heterogeneous mixture is non-homogenized milk.
Since non-homogenized milk is not homogeneous, the cream rises to the top and separates from the rest of the mixture because the emulsion has not been stabilized. However, homogenized milk is just milk whose emulsion has been stabilized the cream does not separate when left to stand.