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Tju [1.3M]
3 years ago
14

Which of these pairs of elements have the same number of valence electrons?

Chemistry
2 answers:
TiliK225 [7]3 years ago
8 0
Berylium(Be) and calcium(Ca)
disa [49]3 years ago
4 0

Answer: Option (b) is the correct answer.

Explanation:

It is known that elements of same group tend to possess same number of valence electrons. As a result, they show same chemical properties.

Phosphorous (P) and chlorine (Cl) belongs to third period. Valence electrons of phosphorous are 5 and chlorine has 7 valence electrons.

Beryllium (Be) and Calcium (Ca) are group 2 elements and both of them have two valence electrons.

Helium (He) is a noble gas and it does not have any valence electrons.

Oxygen (O) has six valence electrons and carbon (C) has 4 valence electrons.

Therefore, we can conclude that berylium (Be) and calcium (Ca) is the pairs of elements have the same number of valence electrons.

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What would you observe in the reaction of calcium with nitric acid​
Marina CMI [18]

Answer:

reacts to form carbondioxide

6 0
3 years ago
1. Use your knowledge of valence electrons and how they affect bonds to figure out how carbon (Group 14) and oxygen (Group 16) w
erik [133]

From the fact that oxygen is in group 16 and carbon is in group 14, the structure of CO2 must be O=C=O. In methane, there is no bond between any of the hydrogen atoms. The structure of H2O2 is H–O–O–H.

Carbon is in group 14 hence it has four valence electrons and oxygen is in group 16 hence it has six valence electrons. This implies that each oxygen atom will share four electrons with carbon in a covalent bond to form the structure O=C=O.

In CH4, we know that carbon is tetravalent so it forms for bonds. Therefore, there is no bond between hydrogen atoms so it bonds with each hydrogen atom; hydrogen only forms one bond.

In H2O2, there is the peroxide ion that has the structure O-O. Hence, the correct structure of H2O2 is H–O–O–H.

Learn more: brainly.com/question/24775418

5 0
3 years ago
If the oxidation number of nitrogen in a certain molecule changes from +3 to -2 during a reaction, is the nitrogen oxidized or r
aliina [53]
The nitrogen has been reduced or has undergone reduction and it has gained one electron
7 0
3 years ago
How many moles are in 3.00x 10^22 atoms of He?
sp2606 [1]

Answer:

<h2>0.05 moles</h2>

Explanation:

To find the number of moles in a substance given it's number of entities we use the formula

n =  \frac{N}{L} \\

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

From the question we have

n =  \frac{3.0 \times  {10}^{22} }{6.02 \times  {10}^{23} }  \\  = 0.049833...

We have the final answer as

<h3>0.05 moles</h3>

Hope this helps you

3 0
3 years ago
Approximately how many moles of chlorine make up 1.79 × 1023 atoms of chlorine?
e-lub [12.9K]
1.2*10^24# atoms of chlorine

Explanation:
Chlorine gas (#Cl_2#) has two atoms of elemental chlorine in a molecule, so:
#1# mol of #Cl_2# have #6*10^23# molecules of #Cl_2#
#1# molecule of #Cl_2# have #2# atoms per molucule
Then #2*6*10^23 = 1.2*10^24# atoms of chlorine in a mol of chlorine gas
6 0
3 years ago
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