First, we need to calculate the principal quantum number n for this electron, using the equation:
E = (-13.60 eV) / (n x n)
where E is the energy that is used to bound the electron (here, E = - 0.544 eV).
- 0.544 eV = (-13.60 eV) / (n x n)
n x n = (- 13.60 eV) / (- 0.544 eV)
n x n = 25
n = 5
The orbital radius that is equal to the radius of a hydrogen atom is calculated using the equation:
r = 0.053 nm x n x n
r = 0.053 nm x 5 x 5
r = 0.053 nm x 25
r = 1.325 nm
Answer:
83.20 g of Na3PO4
Explanation:
1 mole of Na3PO4 contains 3 moles of Na+.
Mole of Na ion to be prepared = Molarity x volume
= 0.700 x 725/1000
= 0.5075 mole
If 1 mole of Na3PO4 contains 3 moles of Na ion, then 0.5075 Na ion will be contained in:
0.5075/3 x 1 = 0.1692 mole of Na3PO4
mole of Na3PO4 = mass/molar mass = 0.1692
Hence, mass of Na3PO4 = 0.1692 x molar mass
= 0.1692 x 163.94
= 83.20 g.
83.20 g of Na3PO4 will be needed.
Answer:
A.) 4.0
Explanation:
The general equilibrium expression looks like this:
![K = \frac{[C]^{c} [D]^{d} }{[A]^{a} [B]^{b} }](https://tex.z-dn.net/?f=K%20%3D%20%5Cfrac%7B%5BC%5D%5E%7Bc%7D%20%5BD%5D%5E%7Bd%7D%20%7D%7B%5BA%5D%5E%7Ba%7D%20%5BB%5D%5E%7Bb%7D%20%7D)
In this expression,
-----> K = equilibrium constant
-----> uppercase letters = molarity
-----> lowercase letters = balanced equation coefficients
In this case, the molarity's do not need to be raised to any numbers because the coefficients in the balanced equation are all 1. You can find the constant by plugging the given molarities into the equation and simplifying.
<----- Equilibrium expression
![K = \frac{[2 M] [2 M]}{[1 M] [1 M] }](https://tex.z-dn.net/?f=K%20%3D%20%5Cfrac%7B%5B2%20M%5D%20%5B2%20M%5D%7D%7B%5B1%20M%5D%20%5B1%20M%5D%20%7D)
<----- Insert molarities
<----- Multiply
<----- Divide
Answer: The correct answer is the option: B. An element with eight valence electrons is chemically unstable.
Explanation:
Hello! Let's solve this!
We will analyze each of the options:
A. The group number of the element provides a clue to the number of valence electrons: it is correct, since it provides the number of valence electrons.
B. An element with eight valence electrons is chemically unstable: this is not correct, since elements with eight electrons in the valence shell cannot react because they already have the last complete shell. Therefore, they are chemically stable.
C. The points must be placed one at a time on each side of the chemical symbol: it is correct, because that is the way to make the point diagram.
D. An atom is chemically stable if all the points are paired: this is correct since this verifies that the point diagram has been done well.
We conclude that the correct answer is the option: B. An element with eight valence electrons is chemically unstable.
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