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
Lelechka [254]
2 years ago
5

The total number of the elements above with 2 valence electron is ____.

Chemistry
1 answer:
OverLord2011 [107]2 years ago
4 0

Answer:

four elements

Explanation:

He = 1s²

Be = 1s² 2s²

C = 1s² 2s² 2p²

Mg = 1s² 2s² 2p⁶ 3s²

Si = 1s² 2s² 2p⁶ 3s² 3p²

Ca = 1s² 2s² 2p⁶ 3s² 3p⁶ 4s²

Valence electrons are those electrons which are present in outer most electronic shell.

He, Be, Mg, Ca these four elements have 2 valence electrons.

While Si and C have four valance electrons.

You might be interested in
Ladididadidaladidadidi
NISA [10]

Answer:

ladidididadaladaddididi

Explanation:

5 0
3 years ago
A solution made by dissolving 33 mg of insulin in 6.5 mL of water has an osmotic pressure of 15.5 mmHg at 25°C. Calculate the mo
Liula [17]

<u>Answer:</u> The molar mass of the insulin is 6087.2 g/mol

<u>Explanation:</u>

To calculate the concentration of solute, we use the equation for osmotic pressure, which is:

\pi=iMRT

Or,

\pi=i\times \frac{\text{Mass of solute}\times 1000}{\text{Molar mass of solute}\times \text{Volume of solution (in mL)}}\times RT

where,

\pi = osmotic pressure of the solution = 15.5 mmHg

i = Van't hoff factor = 1 (for non-electrolytes)

Mass of solute (insulin) = 33 mg = 0.033 g   (Conversion factor: 1 g = 1000 mg)

Volume of solution = 6.5 mL

R = Gas constant = 62.364\text{ L.mmHg }mol^{-1}K^{-1}

T = temperature of the solution = 25^oC=[273+25]=298K

Putting values in above equation, we get:

15.5mmHg=1\times \frac{0.033\times 1000}{\text{Molar mass of insulin}\times 6.5}\times 62.364\text{ L.mmHg }mol^{-1}K^{-1}\times 298K\\\\\text{molar mass of insulin}=\frac{1\times 0.033\times 1000\times 62.364\times 298}{15.5\times 6.5}=6087.2g/mol

Hence, the molar mass of the insulin is 6087.2 g/mol

8 0
3 years ago
Score:
pishuonlain [190]
Some of the NH₄+ will combine with the OH- and shift the equilibrium backwards and from NH₄OH to balance the change produced by addition of NH₄+ ions.
5 0
3 years ago
What is an acid<br>Define the term reactivity action<br>What is a compound​
valentinak56 [21]

Answer:

Acids are water-soluble and acidic chemical compounds, often expressed as the general formula HₓA.

6 0
3 years ago
Read 2 more answers
State and explain modern periodic table. ⊕⊕
Svetradugi [14.3K]

Explanation:

the physical and chemical properties of an element are periodic functions of their atomic number.

7 0
3 years ago
Read 2 more answers
Other questions:
  • On the basis of the Ksp values below, what is the order of the solubility from least soluble to most soluble for these compounds
    12·2 answers
  • When an atom in a reactant gains electrons, what happens to its oxidation number?
    8·1 answer
  • If 25.3 grams of mercury(II) oxide react to form 23.4 grams of mercury, how many grams of oxygen must simultaneously be formed?
    12·1 answer
  • "Science" and "technology are words that often are mixed up, even though they have
    14·1 answer
  • Which is the best method for organizing information collected in an investigation? Plz help
    10·2 answers
  • For which of the following molecules or ions does the following description apply? "The bonding can be explained using a set of
    12·2 answers
  • What block does sodium belong to? s-block p-block d-block or f-block
    9·2 answers
  • Most of earths fresh water is in glaciers <br><br> True or false <br><br> PEASE HELPP
    15·2 answers
  • Photosynthesis uses all of the following except __ to make food ?<br>​
    7·1 answer
  • POINTSSS AND BRAINLIEST IF YOU ANSWER CORRECTLY!!! Write about the law of conservation of energy and where light energy goes. th
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!