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3 years ago

Which element has a 4s sublevel with 2 electrons for its outermost electrons.

Chemistry

2 answers:

Margarita [4]3 years ago

6 0

The answer to thiswould be calcium

Papessa [141]3 years ago

3 0

Answer:

Calcium

Explanation:

Hi!

So, the best way to solve this is with a period table with all of the sublevels labeled. (check below)

So the s sublevel starts at 1s which is Hydrogen. If you go down 4 rows, or periods, you get to sublevels 4s. As you should know, as you go across groups/columns, the valence electrons get higher. So the element that you are looking for has 2 valence electrons. So, the element you are looking for should be 4 down and 1 right of Hydrogen which is: Calcium

I hope I helped and have a wonderful evening!

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A sample of TNT, C7H5N3O6 , has 8.94 × 1021 nitrogen atoms. How many hydrogen atoms are there in this sample of TNT?

Bess [88]

Answer:

1.49×10²² atoms of H are contained in the sample

Explanation:

TNT → C₇H₅N₃O₆

1 mol of this has 7 moles of C, 5 moles of H, 3 moles of N and 6 moles of O

Let's determine the mass of TNT.

Molar mass is = 227 g/mol

As 1 mol has (6.02×10²³) NA atoms, how many moles are 8.94×10²¹ atoms.

8.94×10²¹ atoms / NA = 0.0148 moles

So this would be the rule of three to determine the mass of TNT

3 moles of N are in 227 g of compound

0.0148 moles of N are contained in (0.0148 .227) / 3 = 1.12 g

Now we can work with the hydrogen.

227 grams of TNT contain 5 moles of H

1.12 grams of TNT would contain (1.12 .5) / 227 = 0.0247 moles

Finally let's convert this moles to atoms:

0.0247 mol . 6.02×10²³ atoms / 1 mol = 1.49×10²² atoms

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What is the ph of a solution made by mixing 25.00 ml of 0.100 m hcl with 40.00 ml of 0.100 m koh? assume that the volumes of the

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