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3 years ago

What element has 2 electrons in the 4s sub level?

1 answer:

4 0

is the Calcium because the calcium in group two which group two has 2 electron and also calcium and Potassium 4s sub level group potassium has 1 electron. :)

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What are some examples of some monotonic ions found in the body and how do they affect the body? Please help, anything will help

Luba_88 [7]

Atoms are electrically neutral because the number of protons, which carry a 1+ charge, in the nucleus of an atom is equal to the number of electrons, which carry a 1- charge, in the atom. The result is that the total positive charge of the protons cancels out the total negative charge of the electrons so that the net charge of the atom is zero. Most atoms, however, can either gain or lose electrons; when they do so, the number of electrons becomes different from the number of protons in the nucleus. The resulting charged species is called an ion.

4 0

3 years ago

On the first day of your new job as a chemist, you are given a bottle of magnesium sulfate and asked to make 30 mL of 0.3 M MgSO

Lady bird [3.3K]

Answer:

The answer to your question is 15500 mg of MgSO₄ 7H₂O

Explanation:

Data

Volume = 30 ml

Concentration = 0.3 M

Formula MgSO4∗7H2O

Process

1.- Calculate the number of moles needed

Molarity = moles / volume

Solve for moles

moles = Molarity x volume

Substitution

moles = 0.3 x 0.03 l

moles = 0.009 moles of MgSO₄

2.- Calculate the molecular mass of MgSO4∗7H2O

molecular mass = 24 + 32 + 64 + 14 + 112

= 246 g

3.- Get the proportion MgSO4 :7H2O, this proportion is 1 : 7

4.- Calculate the amount of MgSO4∗7H2O

$0.009 mol of MgSO4 \frac{7 MgSO4 7H2O}{1 mol MgSO4} \frac{246 g MgSO4 7H2O}{1 mol MgSO4 7H2O}$

Simplification

15.5 g = 15500 mg

5 0

3 years ago

If a concentration of 10 fluorescent molecules per μm2of cell membrane is needed to visualize a cell under the microscope, how m

lara [203]

Answer : Total molecules that will be needed to visualize a single egg will be 78500 molecules of dye.

Explanation : As a single egg cell has an approximately diameter of 100 μm.

We can use this formula to calculate area of the cell membrane;

A = π $(100)^{2} / 4$ ;

We can take π as 3.14 and we get;

A = 3.14 X $(100)^{2} / 4$

Soving we get;

A = 7850 μ $m^{2}$

Here we have to calculate the amount of dye molecules which will be needed for 10 fluorescent molecules / μ $m^{2}$ but;

here 1 μ $m^{2}$ = 7850 μ $m^{2}$ dye molecules.

Therefore, 10 fluorescent molecules will need;

7850 X 10 = 78500 molecules of dye.

Therefore, the answer is 78500 molecules of dye.

6 0

3 years ago

A reaction mechanism has the following elementary step as the slow step: B2A What is the rate law for this elementary step? O ra

xenn [34]

Answer:

r = k [ B ]

Explanation:

B → 2A

⇒ r = k [ A ]/2 = k [ B ]

3 0

3 years ago

Explain, in terms of element classification, why KBr is an ionic compound

enot [183]

LBr is ionic compound because k for potassium is metal which means it’s on the left side of the periodic table and Br which is bromine is a non metal which means is on the right side of the periodic table.

In Conclusion when a non metal and metal come together the are called ionic compound

5 0

3 years ago