Answer:
1) 8 valence electrons are a full shell that makes the atom more stable.
Explanation:
Due to the octet rule, atoms tend to form compounds in ways that give them eight valence electrons and thus give them the electron configuration of a noble gas, making them stable.
<span>The electronegativity of the element Se is 2.4, the electronegativity of the element S is 2.5, so the difference between the electronegativity of the elements is 0.1. The probable bond type is non polar covalent bond. Based on the electronegativity values mentioned S is more electronegative.</span>
<span>The answer is Gaseous metals</span>
Answer:
The volume (mL) of 0.135 M NaOH that is required to neutralize 13.7 mL of 0.129 M HCl is 13.1 mL (option b).
Explanation:
The reaction between an acid and a base is called neutralization, forming a salt and water.
Salt is an ionic compound made up of an anion (positively charged ion) from the base and a cation (negatively charged ion) from the acid.
When an acid is neutralized, the amount of base added must equal the amount of acid initially present. This base quantity is said to be the equivalent quantity. In other words, at the equivalence point the stoichiometry of the reaction is exactly fulfilled (there are no limiting or excess reagents), therefore the numbers of moles of both will be in stoichiometric relationship. So:
V acid *M acid = V base *M base
where V represents the volume of solution and M the molar concentration of said solution.
In this case:
- V acid= 13.7 mL= 0.0137 L (being 1,000 mL= 1 L)
- M acid= 0.129 M
- V base= ?
- M base= 0.135 M
Replacing:
0.0137 L* 0.129 M= V base* 0.135 M
Solving:

V base=0.0131 L = 13.1 mL
<u><em>
The volume (mL) of 0.135 M NaOH that is required to neutralize 13.7 mL of 0.129 M HCl is 13.1 mL (option b).</em></u>
For sodium, it has 1 valence electron
For oxygen, it has 6 valence electrons
For iron, it has 2 valence electrons