1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
lakkis [162]
3 years ago
5

How many core electrons are in a ground state atom of selenium?

Chemistry
1 answer:
Harman [31]3 years ago
3 0
Electrons in an atom can be classified as core electrons and valence electrons. Valence electrons are those electrons which are present in valence shell and participates in bond formation. While, Core electrons are all remaining electrons which are not present in valence shell, hence not take part in bonding.

Atomic number of Selenium (Se) is 34 hence it has 34 electrons with following electronic configuration;

                          1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁴

From electronic configuration it is found that the valence shell is 4, and the number of electrons present in valence shell are 6. So, 

             Core Electrons  =  Total Electrons - Valence Electrons

             Core Electrons  =  34 - 6

             Core Electrons  =  28

Result:
          There are 28 core electrons in Selenium.
You might be interested in
Cosmic rays are
IrinaK [193]

A. High energy radiation produced in the ozone layer. (:

6 0
2 years ago
For the following reaction, 6.94 grams of water are mixed with excess sulfur dioxide . Assume that the percent yield of sulfurou
Alexxx [7]
<h3>Answer:</h3>

#a. Theoretical yield = 31.6 g

#b. Actual yield = 25.72 g

<h3>Explanation:</h3>

The equation for the reaction between sulfur dioxide and water to form sulfurous acid is given by the equation;

SO₂(g) + H₂O(l) → H₂SO₃(aq)

The percent yield of H₂SO₃ is 81.4%

Mass of water that reacted is 6.94 g

#a. To get the theoretical yield of H₂SO₃ we need to follow the following steps

Step 1: Calculate the moles of water

Molar mass of water = 18.02 g/mol

Mass of water = 6.94 g

But, moles = Mass/molar mass

Moles of water = 6.94 g ÷ 18.02 g/mol

                        = 0.385 mol

Step 2: Calculate moles of H₂SO₃

From the equation, the mole ratio of water to H₂SO₃ is 1 : 1

Therefore, moles of water = moles of H₂SO₃

Hence, moles of H₂SO₃ = 0.385 mol

Step 3: Theoretical mass of H₂SO₃

Mass = moles × Molar mass

Molar mass of H₂SO₃ = 82.08 g/mol

Number of moles of H₂SO₃ = 0.385 mol

Therefore;

Theoretical mass of H₂SO₃ = 0.385 mol ×  82.08 g/mol

                                             = 31.60 g

Thus, the theoretical yield of H₂SO₃ is 31.6 g

<h3>#b. Calculating the actual yield</h3>

We need to calculate the actual yield

Percent yield of H₂SO₃ is 81.4%

Theoretical yield is 31.60 g

But; Percent yield = (Actual yield/theoretical yield)×100

Therefore;

Actual yield = Percent yield × theoretical yield)÷ 100

                   = (81.4 % × 31.6) ÷ 100

                  = 25.72 g

The percent yield of H₂SO₃ is 25.72 g

6 0
2 years ago
Chemistry. hellppp. pls
AveGali [126]
Carbon dioxide consists of the elements Carbon (C) and Oxygen (O) and you have to have 2 oxygen.
6 0
2 years ago
Match the term with the definition.
alina1380 [7]
What term and what definition..
5 0
3 years ago
Read 2 more answers
Why is water important?​
expeople1 [14]

Answer:

Its a natural resource used around the world

4 0
2 years ago
Other questions:
  • A. What are the products for this chemical Equation? B. What kind of Reaction is this?
    9·1 answer
  • How does Elnora feel about her future? A) She takes one day at a time. B) She is apprehensive and anxious. C) She is optimistic
    10·1 answer
  • given the balanced equation representing a reaction 2NO+O2-&gt;2NO2+energy the mole ratio of NO to NO2 IS
    5·1 answer
  • - The subatomic particle possessing the largest
    7·1 answer
  • A mixture was found to contain 1.05g of SiO2, 0.69g of cellulose and 1.82g of calcium carbonate. What percentage of calcium carb
    13·2 answers
  • Please help... I’m trying to study for a test and I can’t find any information on these questions.
    5·1 answer
  • Why Are Bees Important To The Environment/Ecosystem
    9·1 answer
  • If you leave a cup of hot chocolate sitting on a table what eventually happens to the temperature? Does the temperature ever rea
    14·1 answer
  • How many grams of aluminum oxide (Al2O3) will be formed from 10.0 grams of aluminum (Al)? 4 AL + 3 02 --&gt; 2 AL203​
    5·1 answer
  • 4. Why does the metallic character of the alkaline earth metals increase as you go down the
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!