The mass number = protons + neutrons. Bromine has a mass number of 80<span> and 35 protons so </span>80<span>-35 = </span>45<span> neutrons. b) How many electrons does the neutral atom of bromine have? The neutral atom of bromine has 35 electrons because the number of electrons equals the number of protons.</span>
Hello!
When finding the chemical formula of a compound, we will need to find the charges of each element/bond.
Looking at our period table, sodium has a +1 charge, written as Na 1+, and sulfate has a charge of -2, and it is written as SO4 2-.
Now, we need to make the charges equivalent. To do this, we need to "criss-cross" the charges. This means that sodium will need to additional atoms to make the charges equal, and sulfate will need one.
Therefore, the chemical formula for sodium sulfate is: Na2SO4.
Electron structure of sodium:
₁₁Na: 1s²2s²2p⁶3s¹
Explanation:
Atomic number is defined as the number of an element which represents total number of protons.
When an atom is neutral then it means it contains same number of protons and electrons.
On the other hand, atomic mass is defined as the sum of total number of protons and neutrons present in an atom.
Protons of every element remains fixed because it shows the identity of each element but if we change the number of neutrons then also identity of the atom will remain fixed. This is because changing the number of neutrons will not show any change in number of protons.
For example, 
and 
are isotopes of hydrogen and they have same number of protons but different number of neutrons.
Thus, we can conclude that number of neutrons can vary without changing the identity of the element.
Since the water is at 100 degrees then it take 40.6 kj/mol to change 1 mole of water at 100 degrees into steam at 100 degrees
the moles of water 8.22mol
since one mole take 40.6kj/mol 8.22mol will be =
8.22mol x 40.6 kj/mol =333.732 kj
