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3 years ago

12

I thought in the third shell there are 18 electrons, but why are they gaining only 2 electrons?? Pls tell me... I have exam tomo

rrow....

2 answers:

blsea [12.9K]3 years ago

7 0

Use this picture to understands.

AlexFokin [52]3 years ago

4 0

The picture will help you understand

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A chemistry student needs 40.0 mL of pentane for an experiment. By consulting the CRC Handbook of Chemistry and Physics, the stu

Alenkinab [10]

Answer:

25.04 g is the mass of pentane

Explanation:

Pentane density = Pentane mass / Pentane volume

1 cm³ = 1mL

0.626 g/mL = Pentane mass / Pentane volume

0.626 g/mL = Pentane mass / 40 mL

0.626 g/mL . 40 mL = Pentane mass → 25.04 g

5 0

3 years ago

For a given mass of reactants, the energy released is greatest for a reaction involving

kari74 [83]

Answer: Option (D) is the correct answer.

Explanation:

In fusion reaction, two small nuclei combine together to result in the formation of a large nuclei.

Whereas in fission reaction, large nuclei dissociates into two or more small nuclei.

Nuclear fusion releases more energy as compared to nuclear fission.

For example, two hydrogen nuceli fuse together and result in the formation of helium atom along with release of energy.

$^{2}_{1}H + ^{2}_{1}H \rightarrow ^{4}_{2}He + Energy$

3 0

3 years ago

Read 2 more answers

Hello wonderful people and Good morning, or afternoon

PtichkaEL [24]

He sounds so cute!!!!!

6 0

3 years ago

A chemist makes a solution of NaOH for use in an experiment. She dissolves 0.00500 mol NaOH in 1.00 L H2O. The NaOH completely d

anygoal [31]

Answer:

pH = 11.7

Explanation:

<u>Given:</u>

[OH-] = 0.00500 M

<u>To determine:</u>

pH of the solution

<u>Explanation:</u>

pH refers to the H+ ion concentration in a given solution whereas pOH indicates the OH- ion concentration.

pH and pOH are related by the following equation:

$pH + pOH = 14 ------(1)$

Here:

$pH = -log[H+]\\\\pOH = -log[OH-]$

When OH- = 0.00500 M

$pOH = -log(0.00500) = 2.30\\$

Based on equation(1):

$pH = 14 - pOH = 14 -2.30=11.7$

6 0

4 years ago

A radioactive isotope of potassium (k) has a half-life of 20 minutes. if a 43 gram sample of this isotope is allowed to decay fo

Ksenya-84 [330]

Hello!

The half-life is the time of half-disintegration, it is the time in which half of the atoms of an isotope disintegrate.

We have the following data:

mo (initial mass) = 43 g

m (final mass after time T) = ? (in g)

x (number of periods elapsed) = ?

P (Half-life) = 20 minutes

T (Elapsed time for sample reduction) = 80 minutes

Let's find the number of periods elapsed (x), let us see:

$T = x*P$

$80 = x*20$

$80 = 20\:x$

$20\:x = 80$

$x = \dfrac{80}{20}$

$\boxed{x = 4}$

Now, let's find the final mass (m) of this isotope after the elapsed time, let's see:

$m = \dfrac{m_o}{2^x}$

$m = \dfrac{43}{2^{4}}$

$m = \dfrac{43}{16}$

$\boxed{\boxed{m = 2.6875\:g}}\end{array}}\qquad\checkmark$

I Hope this helps, greetings ... DexteR! =)

8 0

4 years ago