Answer:
51.53 grams .
Explanation:
Na₃PO₄ ⇄ 3Na⁺¹ + PO₄⁻³ .
1 mole 3 mole
725 mL of 1.3 M Na⁺ ions
= .725 x 1.3 moles of Na⁺ ions
= .9425 moles
3 mole of Na⁺ is formed by 1 mole of Na₃PO₄
.9425 mole of Na⁺ is formed by .9425/3 mole of Na₃PO₄
Na₃PO₄ needed = .9425/3 moles = .3142 moles
Molecular weight of Na₃PO₄ = 164
grams of Na₃PO₄ needed = .3142 x 164 = 51.53 grams .
I will take a stab at it, but there are not equations, did you forget them?
Electrons in an atom can be classified as core electrons and valence electrons. Valence electrons are those electrons which are present in valence shell and participates in bond formation. While, Core electrons are all remaining electrons which are not present in valence shell, hence not take part in bonding.
Atomic number of Selenium (Se) is 34 hence it has 34 electrons with following electronic configuration;
1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁴
From electronic configuration it is found that the valence shell is 4, and the number of electrons present in valence shell are 6. So,
Core Electrons = Total Electrons - Valence Electrons
Core Electrons = 34 - 6
Core Electrons = 28
Result:
There are 28 core electrons in Selenium.
<u>Answer:</u>
All living things are not made of cells.
<span>Valence electrons are important because these are the only electrons involved with an atom's chemical reactivity.</span>
