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3 years ago

Which statement accurately describes the atoms of a specific element?

2 answers:

s2008m [1.1K]3 years ago

5 0

Answer: the correct answer is 100% B. scandium‚ Sc‚ atom contains 45 electrons outside the nucleus and 21 neutrons inside the nucleus. just took the test and got it right

katrin2010 [14]3 years ago

4 0

Answer: The correct answer is Option D.

Explanation:

Atomic number is defined as the number of electrons or number of protons that are present in a neutral atom. It is represented as Z.

Z = Atomic number = Number of electrons = Number of protons

Mass number is defined as the sum of number of protons and number of neutrons present in an atom. It is represented as A.

A = Mass number = Number of protons + Number of neutrons

Number of neutrons = Mass number - Atomic number

For the given options:

Option A:

Indium is the 49th element of the periodic table having mass number 115.

So, Number of protons = Number of electrons = 49

Number of neutrons = 115 - 49 = 66

Hence, this is not correctly described.

Option B:

Scandium is the 21st element of the periodic table having mass number 45

So, Number of protons = Number of electrons = 21

Number of neutrons = 45 - 21 = 24

Hence, this is not correctly described.

Option C:

Aluminium is the 13th element of the periodic table having mass number 27

So, Number of protons = Number of electrons = 13

Number of neutrons = 27 - 13 = 14

Hence, this is not correctly described.

Option D:

Zinc is the 30th element of the periodic table.

So, Number of protons = Number of electrons = 30

This atom has 30 protons inside the nucleus and 30 electrons outside the nucleus.

Hence, this is correctly described.

Thus, the correct answer is Option D.

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White raven [17]

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enyata [817]

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3 years ago

A solution contains one or more of the following ions: Ag , Ca2 , and Co2 . Lithium bromide is added to the solution and no prec

koban [17]

Answer:

$Ca^{2+} and Co^{2+}$

Explanation:

Given:

A solution contains one or more of the following ions such as Ag, $Ca_2$ and $Co_2$

Here the Lithium bromide is added to the solution and no precipitate forms

Solution:

Since with LiBr no precipitation takes place therefore Ag+ is absent

Here on adding $Li_2SO_4$ to it precipitation takes place.

Precipitate is as follows,

$Ca^{2+}(aq)+SO_4^2^-(aq)----->CASO_4(s)$

Thus,

$Ca^2^+$ is present

When $Li_3PO_4$ is added again precipitation takes place.

Therefore the reaction is as follows,

$Co^2^+(aq)+PO_4^3^-(aq)------>Co_3(PO_4)_2(s)$

Therefore,

$Ca^{2+} and Co^{2+}$ are present in the solution

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3 years ago

Buffering capacity refers to: the effectiveness of commercial antacids the extent to which a buffer solution can counteract the

kirill [66]

Answer: Option (b) is the correct answer.

Explanation:

Buffere is defined as the solution to whom when an acid or base is added then it resists any in change in pH of the solution.

This is because a buffer has the ability to not get affected by the addition of small amounts of an acid or a base. So, basically it keeps the concentration of both hydrogen ions and hydroxides equal. As a result, it helps in maintaining the pH of the solution.

And, the capacity of a buffer solution to resist the change is known as buffer capacity.

Thus, we can conclude that buffering capacity refers to the extent to which a buffer solution can counteract the effect of added acid or base.

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3 years ago

Please help me !!!!!!!!! i'll give brainlist !

qwelly [4]

Answer:

A-B

C-D

E-F

I think it's these because Potential Energy increase when the graph increases and remain constant when the graph is flat.

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3 years ago