Answer:
Barium has the same number of valence electrons as calcium
Explanation:
Valence electrons is the number of electrons of an atom on the outer shell.
Those valence electrons can participate in the formation of a chemical bond (if the outer shell is not closed); in a single covalent bond, both atoms in the bond contribute one valence electron in order to form a shared pair.
<u>Calcium</u> is an atom, part of group 2, called the alkaline earth metals. The alkaline earth metals have 2 valence electrons.
<u>Sulfur </u>is part of a group 16, called the chalcogens or oxygen family. Those atoms have 6 valence electrons. They can form a bound with atoms of group 2 such as calcium, but do not have the same number of valence electrons.
<u>Potassium</u> is part of group 1, called the alkali metals or lithium family. Those atoms have 1 valence electrons. That means Potassium do not have the same number of valence electrons like calcium.
<u>Neon</u> is part of group 18, the noble gasses. Those are stable atoms, which means they have 8 valence electrons. They do not have the same number of valence electrons like Calcium.
<u>Barium</u> an atom, part of group 2, called the alkaline earth metals. The alkaline earth metals have 2 valence electrons. Calcium is also part of this group.
This means barium has the same number of valence electrons as Calcium.
Mg(OH)₂ ⇄ Mg²⁺ + 2 OH⁻
Ksp = [Mg²⁺] [OH⁻]²
6.0 x 10⁻¹⁰ = 0.10 x [OH⁻]²
[OH⁻] = 7.746 x 10⁻⁵ M
when Mg(OH)₂ 1st precipitates, [OH⁻] = 7.746 * 10⁻⁵ M
Fe(OH)₂ <—> Fe²⁺ + 2OH⁻
Ksp = [Fe²⁺] [OH⁻]²
7.9 x 10⁻¹⁶ = [Fe²⁺] x (7.746 x 10⁻⁵)²
[Fe²⁺] = 1.32 x 10⁻⁷ M
Answer: 1.32 x 10⁻⁷ M
Answer:
1 and 2
Explanation:
1. The moon blocks the sun's light from hitting the Earth. (It casts a shadow on the earth by doing so)
2. The moon moves between the Earth and the Sun. (So it blocks the sun's light)
