1. Boron has two naturally occurring isotopes, boron-10 and boron-11. Boron-10 has a mass of 10.0129 relative to carbon-12 and makes up 19.78 percent of all naturally occurring boron. Boron-11 has a mass of 11.00931 compared to carbon-12 and makes up the remaining 80.22 percent. What is the atomic weight of boron?

2. Identify the number of protons, neutrons, and electrons in the following isotopes:
a. 147N b. 3517Cl c. 4820Ca d. 6329Cu e. 23092U

3. How many outer shell electrons are found in an atom of
a. Na? b. P? c. Br? d. I? e. Te?

4. Use the periodic table to identify if the following are metals, nonmetals, or semiconductors:
a. Radon b. Francium c. Arsenic d. Phosphorus e. Hafnium

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pstnonsonjoku pstnonsonjoku · Answer 1 · 2022-07-22T22:05:37+02:00

From the calculation, the atomic weight of the boron atom is 10.812.

We can find the atomic weight of boron from;

(19.78/100 * 10.0129) + ( 80.22/100 * 11.00931)

= 1.981 + 8.831

= 10.812

The number of protons, neutrons, and electrons in the following isotopes are;

N - 7 electrons, 7 protons and 7 neutrons

Cl - 17 electrons, 17 protons and 18 neutrons

Ca - 20 protons, 20 electrons and 28 neutrons

Cu - 29 protons, 29 electrons and 3 neutrons

U - 92 protons, 92 electrons and 138 neutrons

The number of outer shell electrons in the atoms are;

Na - 1

P - 5

Br - 7

I - 7

Te - 6

The elements are classified as follows;

Radon - nonmetal

Francium - metal

Arsenic - semiconductor

phosphorus - nonmetal

Hafnium - metal

Learn more about the periodic table:https://brainly.com/question/11155928

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