All categories

4 years ago

Help Me Please

2 answers:

6 0

in the periodic table, elements are classified in the ascending order of their atomic numbers. atomic number is the number of protons

in elements the number of protons is equal to the number of electrons

the condensed notation of electron configuration is when the symbol of the noble gas closest to the elements electron configuration is mentioned.

[He] 2s² - number of electrons in He is 2 , and 2 more electrons in the s subshell adds upto a sum of 4 electrons. number of protons = number of electrons

then number of protons = 4

then atomic number is 4. element with atomic number 4 is Be

the element is Be

[Ne] 3s² 3p⁵

Ne atomic number is 10. 10 + 7 electrons in the third shell = 17 electrons in total

atomic number - 17 is Cl

element is Cl

[Xe] 6s¹

Xe atomic number is 54, 54 + 1 electron in the sixth shell = 55 electrons in total

atomic number of 55 is Cs

element is Cs

[Ar] 4s² 3d⁹

Ar atomic number is 18. 18 + 2 electrons in 4th shell and 9 in d subshell of 3rd shell = 29 electrons in total

atomic number of 29 is Cu

element is Cu

Shtirlitz [24]4 years ago

6 0

[He]2s2: Be
[Ne]3s23p5: Cl
[Xe]6s1: Cs
<span> [Ar]4s23d9: Cu</span>

You might be interested in

Copy and complete the following concept map on chemical Reactions

ExtremeBDS [4]

Can you attach the following concept map on chemical reactions?

5 0

3 years ago

Consider the following reaction where K. = 154 at 298 K: 2NO(g) + Brz(9) 2NOBr(g) A reaction mixture was found to contain 2.69x1

bekas [8.4K]

Explanation:

$2NO(g) + Br_2(g)\rightleftharpoons 2NOBr(g)$

Equilibrium constant of reaction = $K=154$

Concentration of NO = $[NO]=\frac{2.69\times 10^{-2} mol}{1 L}=2.69\times 10^{-2} M$

Concentration of bromine gas = $[Br_2]=\frac{3.85\times 10^{-2} mol}{1 L}=3.85\times 10^{-2} M$

Concentration of NOBr gas = $[Br_2]=\frac{9.56\times 10^{-2} mol}{1 L}=9.56\times 10^{-2} M$

The reaction quotient is given as:

$Q=\frac{[NOBr]^2}{[NO]^2[Br_2]}=\frac{(9.56\times 10^{-2} M)^2}{(2.69\times 10^{-2} M)^2\times 3.85\times 10^{-2} M}$

$Q=328.06$

$Q>K$

The reaction will go in backward direction in order to achieve an equilibrium state.

1. In order to reach equilibrium NOBr (g) must be produced. False

2. In order to reach equilibrium K must decrease. False

3. In order to reach equilibrium NO must be produced. True

4. Q. is less than K . False

5. The reaction is at equilibrium. No further reaction will occur. False

8 0

3 years ago

Is the reaction mg²⁺(aq) + h₂o(l) → mgo(s) + 2h⁺(aq) endothermic or exothermic?

aliya0001 [1]

<span>If energy is released, the reaction is exothermic. If energy is absorbed, the reaction is endothermic. Since heat is being absorbed in this reaction (to break down H2O into H2 and O), the reaction is endothermic.</span>

3 0

3 years ago

I don’t understand how to do this

padilas [110]

Answer:

do what?????

Explanation:

6 0

3 years ago

What will happen wen lead react with copper 2 sulfate

dezoksy [38]

Answer:This is what's known as a metal displacement reaction: the lead substitutes for the copper and ends up precipitating out of solution as insoluble lead (II) sulfate. ... The weight of copper deposited was 15.86gm.

Explanation:

4 0

3 years ago