H2O, also known as water, stands for two hydrogen atoms and one oxygen atom. Hope this helps! ^^
I think the correct answer is option 3. CaCl2 is the compound that is an electrolyte when dissolved in water. An electrolyte is a substance that conducts electricity in solution. Calcium Chloride when in solution dissociates into ions which allows the flow of current in the solution.
Answer: Halogens tend to attract electrons when bonding (Option C)
Explanation: Halogens being non metals have greater electronegativities hence, attract electrons and making the statement disputed. Nobel gases are highly stable; this explains why they are nonreactive. They do not form chemical bonds because they only have a little tendency to either gain or lose an electron; on the other hand, halogens are reactive because they only need one additional electron to complete their octet.
Magnesium :
<span>[Ne] 3s²</span>
Answer A
hope this helps!