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Nesterboy [21]
3 years ago
13

What is true about the element calcium(Ca, atomic number 20)? Choose all that apply.

Chemistry
2 answers:
Marat540 [252]3 years ago
7 0
It has 2 valence electrons

THANK ME
Shkiper50 [21]3 years ago
5 0

Answer:

It has 2 valence electrons

It is a metal.

Explanation:

Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal.

In chemistry, a metal is an element that readily forms positive ions (cations) by losing electrons.

Calcium belongs to group 2 and would give up it's two valence electrons in reactions.

The electronic configuration is given as;

Ca : 1s2 2s2 2p6 3s2 3p6 4s2 or [Ar] 4s²

Valence electron represents the outermost electrons.

The correct options are;

It has 2 valence electrons

It is a metal.

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Which of the following is least likely to increase the rate of diffusion?A small concentration gradientB higher concentration of
Ksenya-84 [330]

Answer: Option (A) is the correct answer.

Explanation:

Rate of diffusion is defined as the total movement of molecules from a region of higher concentration to lower concentration.

The interaction between medium and the material is responsible for the rate of diffusion of a material or substance.

A small concentration gradient means small difference in the number of molecules taking part in a reaction. So, when there no large difference between the concentration then there won't be much difference in the rate of diffusion of a material.

Whereas a higher concentration of molecules will lead to more number of collisions due to which frequency of molecules increases. Therefore, rate of diffusion will also increase.

Small molecule size will also lead to increases in rate of diffusion. This is because according to Graham's law rate of diffusion is inversely proportional to molar mass of an element. Hence, smaller size molecule will have smaller mass. As a result, rate of diffusion will be more.

High temperature means more kinetic energy of molecules due to which more number of collisions will be there. Hence, rate of diffusion will also increase.

Thus, we can conclude that out of the given options a small concentration gradient  is least likely to increase the rate of diffusion.

4 0
3 years ago
Refer to your periodic table:
Mazyrski [523]

iondine

Explanation:

bromine has 185pm, astatine haa 200, iondine has 140 and lastly fluorine has 147. so iondine has the smallest atomic radius

6 0
3 years ago
Explain how the shorelines can affect the weather, in one to two sentences
defon

Answer:

Global warming causes sea-level rise as oceans expand, and makes storm patterns more energetic. Consequently it will affect most of the world's coastlines through inundation and increased erosion.

<h3><u>PLEASE</u><u> MARK</u><u> ME</u><u> BRAINLIEST</u><u>.</u></h3>
5 0
2 years ago
MARKING BRAINLEIST!!
anastassius [24]

Answer:

B: They are the results of many experiments over a long period of time.

Explanation:

4 0
2 years ago
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2.<br> Why does<br> a chemical equation<br> need to<br> be balanced?
arlik [135]

<em>Answer:</em>

<em>Chemical equations must be balanced to satisfy the law of conservation of matter, that states that matter cannot be produced or destroyed in a closed system. The law of conservation of mass governs the balancing of a chemical equation.</em>

Explanation:

7 0
3 years ago
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