Answer:
See Explanation
Explanation:
1) Let us recall that;
Mass number = number of protons + number of neutrons
Where;
Number of protons = ?
Number of neutrons =20
Mass number =39
Number of protons = mass number - number of neutrons
Mass of protons =39 - 20= 19 protons
2) Atomic number = 13
Number of neutrons =14
Then the mass number =13 +14 =27
The symbol of the element is 27X13
The number of protons= the number of electrons =13
The atomic number is the same as the proton number =13
☃️ Chemical formulae ➝ 
How to find?
For solving this question, We need to know how to find moles of solution or any substance if a certain weight is given.
Solution:
❍ Molecular weight of
= 2 × 126.90
= 253.80
= 254 (approx.)
❍ Given weight: 12.7
Then, no. of moles,
⇛ No. of moles = 12.7 / 254
⇛ No. of moles = 0.05 moles
⚘ No. of moles of Iodine molecule in the given weight = <u>0.05</u><u> </u><u>moles </u>
<u>━━━━━━━━━━━━━━━━━━━━</u>
Water would not expand when it freezes.<span> </span>
Answer:
is the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons, often in conjunction with other chemical changes.
