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ser-zykov [4K]
2 years ago
12

Three elements are represented by the letters A, B, and C. the three elements have the same number of valence electrons. Element

C has electrons in three energy levels and element A is the lightest of the three. Elements B has a total of twenty electrons. Identify the elements.
Chemistry
1 answer:
AfilCa [17]2 years ago
3 0
Answer:
A- beryllium
B- calcium
C- magnesium

Explanation
NOTE: all element in group 2 have 2 balance electrons

First let’s start with B- number of electrons= number of protons which is equal to the atomic number. therefore, the answer is calcium as it’s atomic number is 20

C- magnesium will have three energy levels considering it has 12 electrons (2,8,2).

A- beryllium is the lightest one in group 2 as it has the atomic mass of 9.0122.
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Determine the total number of atoms contain in a 2.00 moles of Ni
spayn [35]

Answer:

2.00 moles of Ni has 1.2 *10^24 atoms

Explanation:

Step 1: Data given

Number of moles Ni = 2.00 moles

Number of Avogadro = 6.022*10^23 /mol

Step 2: Calculate number of atoms

Number of particles (=atoms) = Number of Avogadro *  number of moles

Number of atoms = 6.022 * 10^23 /mol * 2.00 moles

Number of atoms = 1.2*10^24 atoms

2.00 moles of Ni has 1.2 *10^24 atoms

4 0
3 years ago
Number of electrons for all of these even the ones with a number by them ? Will give brainlist!!!!
Bumek [7]

Explanation:

s=2

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d=10

f=14

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7 0
2 years ago
If the temperature on 244 mL of a gas is changed to 488 mL and 6 atm, at constant
Fittoniya [83]

Answer:

<h2>12 atm</h2>

Explanation:

To find the initial pressure we use the formula for Boyle's law which is

P_1V_1 = P_2V_2

Since we are finding the initial pressure

P_1 =  \frac{P_2V_2}{V_1}  \\

From the question we have

P_1 =  \frac{488 \times 6}{244}  =  \frac{2928}{244}  \\

We have the final answer as

<h3>12 atm</h3>

Hope this helps you

6 0
2 years ago
What is the balanced chemical equation for this reaction? H3PO4 + HCl → PCl5 + H2O Question 7 options: H3PO4 + 5HCl → PCl5 + H2O
WITCHER [35]

Answer:

It's the last option.

Explanation:

H3PO4 + 5HCl → PCl5 + 4H2O

4 0
2 years ago
How many mols of chlorine are in 120g of chlorine gas
xz_007 [3.2K]

Answer:

Number of moles of chlorine = 3.38 mol

Explanation:

Given data:

Mass of chlorine = 120 g

Moles of chlorine = ?

Solution:

Formula:

Number of moles = mass/molar mass

Molar mass of chlorine = 35.5 g/mol

Now we will put the values in formula.

Number of moles = 120 g/ 35.5 g/mol

Number of moles = 3.38 mol

6 0
3 years ago
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