Answer:
The number of valence electrons can be known from the group that the element is in (except the lanthanides, actinides and groups 3-12).
Explanation:
Group 1 has 1 valence electron. Group 2 has 2 valence electrons. Group 13 has 3 valence electrons. Group 14 has 4, group 15 has 5, group 16 has 6, group 17 has 7, and group 18 has 8.
Group 18 are the noble gases which are stable.
Group 17 are the halogens and react well with the alkali metals.
<u>158 pm</u> is the distance Between equatorial Fluorine atoms in PF₅<u>(</u>Phosphorus pentafluoride).
<h3>What is
Fluorine?</h3>
The chemical element fluorine has an atomic number of 9 and the symbol F. The lightest halogen, it is an extremely poisonous, pale yellow diatomic gas under normal conditions. It is exceedingly reactive and, as the most electronegative element, reacts with all other elements with the exception of argon, neon, and helium.
Fluorine is the 24th most abundant element overall and the 13th most abundant on Earth. In order to decrease the melting temperatures of metal ores for smelting, fluorite, the main mineral source of fluorine, was added. The Latin verb fluo, which means "flow," gave the mineral its name. Fluorite was first described in 1529.
Learn more about fluorine
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3 teaspoons equal to 1 tablespoon in the metric conversions.
Answer:-
Solution:- It is a simple unit conversion problem. We could solve this using dimensional analysis.
We know that, 1 US dollar = 100 cents
1 cent = 1 US penny
So, 1 US dollar = 100 US pennies
Let's make the set up starting with 1 penny as:
=
Therefore, we can bye of Cf in one US penny.
Let's find the number of moles first.
Number of moles = mass/molar mass
Molar mass = 51.9961
Number of moles = 13/ 51.9961 = 0.2500.
1 mole of any particle contains 6.02 * 10^(23) atoms.
Hence 0.2500 moles contains X
Hence X = 0.25 * 6.022 * 10^(23) = 1.5055 * 10^(23)