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fgiga [73]
4 years ago
15

The atomic number of an element is 20. (a) Write its electronic configuration and determine its valency. (b) Is it a metal or a

non-metal ? (c) Write the formula of its chloride. (d) Is it more reactive or less reactive than Mg (atomic number 12) ? Give reason for your answer.
Chemistry
1 answer:
nataly862011 [7]4 years ago
7 0
A) Me20=1s2 2s2 2p6 3s2 3p6 4s2
or
Me20=2)8)8)2)
The valence electron is 2
b)It is metal- Ca
c) \:  {Ca}^{ + 2}  \: and \:  {Cl}^{ - 1}  \\ form \: CaCl2 \: compound \\


d) it is more reactive than Mg
Becayse,
Calcium electropositive than magnesium
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Which statements are true concerning elements in the same group of the periodic table? Select all that apply.
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The statements A and F are true concerning elements in the same group of the periodic table.  

To select all that apply, we need to evaluate each statement.

A. They have similar periodic properties.  

This statement is true. All the elements in the same group will have similar chemical and physical properties due to the electron configuration of their outer shell. For example, the alkali metals group (Li, Na, K, Rb, Cs, and Fr), has a valence electron configuration of s¹ (in the outer shell), which gives them the tendency to react vigorously with water, as well as other properties.      

B. They are all metals or nonmetals, but not both.

This is false. If we take a look at the p-block of the periodic table, we can see that the <u>groups</u> in this block are conformed by nonmetals, metals, and metalloids. For example, the icosagens group is formed by metalloids (B) and metals (Al, Ga, In, Tl).          

 

C. They are either all solids or all liquids or all gases.

This is false. In some groups, all the elements are solids (alkaline earth metals) or gases (group of noble gases), but in others, the groups are conformed by gases with solids (pnictogens group) or by gases with liquids (halogens group).  

   

D. They have the same number of shells of electrons.

This is false. In a group, the number of shells <u>increases from top to bottom</u> in the periodic table. For example, the electron configuration of the elements in the alkali metals is:        

  • H: 1s¹      
  • Li: [He]2s¹
  • Na: [Ne]3s¹
  • K: [Ar]4s¹
  • Rb: [Kr]5s¹
  • Cs:  [Xe]6s¹
  • Fr: [Rn]7s¹

We can see that hydrogen has 1 shell and Cs has 6 shells.  

E. They have the same number of inner core electrons.

This is false. As we said at point D, the number of shells increases from top to bottom in a group, so the number of inner core electrons also increases in this order. For example, in the alkaline earth metals group, the electron configuration of the elements is:  

  • Be: [He]2s²
  • Mg: [Ne]3s²
  • Ca: [Ar]4s²
  • Sr: [Kr]5s²
  • Ba: [Xe]6s²
  • Ra: [Rn]7s²

As we can see, the number of inner shells increases from Be ([He]) to Ra ([Rn]).    

F. They have the same outer shell electron configuration.

This is true. As we said at point A, the elements in the same group will have the same electron configuration of the outer shell (valence electron configuration). At points D and E, we can see that the valence electron configuration is the same for all the elements in the groups.    

Therefore, statements A and F are true.      

You can find more about the periodic table here: brainly.com/question/4287157?referrer=searchResults

I hope it helps you!    

           

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The molecular weight of table salt, NaCl, is 58.5 g/mol. A tablespoon of salt weighs 6.37 grams. Calculate the number of moles o
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There are 0.109 moles of NaCl in one tablespoon of salt. This is found by dividing the number of grams you have by the molecular weight.
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Hey there!:

The hydroxyl groups act to neutralize the sodium borohydride which reduces yield.


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