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Brrunno [24]
3 years ago
13

How did Henry Moseley revise Mendeleev's periodic table? (Please answer A.S.A.P.)

Chemistry
2 answers:
CaHeK987 [17]3 years ago
5 0
<span>If you give it a good search, the most used answer would probably be as follows,

</span><span>In 1914 Henry Moseley found a relationship between an element's X-ray wavelength and its atomic number (Z), and therefore rearranged the table by nuclear charge / atomic number rather than atomic weight. Before this discovery, atomic numbers were just sequential numbers based on an element's atomic weight. Moseley's discovery showed that atomic numbers had an experimentally measurable basis.
</span>
Hope this helps!
jekas [21]3 years ago
5 0

Answer:

Arranged the elements on the table in order of increasing number of protons, or atomic number.

Explanation:

Mendeleev listed the known chemical elements in ascending order of atomic mass. However, such classification gave some problems to Mendeleev's table, which was characterized by the impression that some elements appeared to be out of place. An example was argon which, when isolated, did not appear to have the correct mass to justify its position. Its relative atomic mass of 40 is the same as that of calcium, but these differed considerably: while argon is an inert gas, calcium is a very reactive metal.

In the early twentieth century, when Henry Moseley examined the x-ray spectrum of the elements, he found that all atoms of the same chemical element had the same nuclear charge, and therefore had the same number of protons, which consist of the atomic number of the elements. It was quickly concluded that the elements would be in an even more regular pattern when arranged in a table in ascending order of their atomic number rather than atomic mass.

Thus, we can conclude that Moseley revised Mendeleev's periodic table by arranging the elements on the periodic table in ascending order of proton number or atomic number.

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According to the reaction below, what mass of oxygen gas is required to produce 22 g of carbon dioxide?
alisha [4.7K]
The answer is B)4.0g
6 0
3 years ago
Which of these electron transitions correspond to absorption of energy and which to emission?
Keith_Richards [23]

The electron transitions representing absorption of energy are:

(a) n = 2 to n = 4

(d) n = 3 to n = 4

and those which represents emissions of energy are:

(b) n = 3 to n = 1

(c) n = 5 to n = 2

An electron emits energy when it jumps from a higher energy level to a lower energy level transitions.

An electron absorbs energy to jump from a lower energy level to a higher energy level transitions.

(a) n = 2 to n = 4

Here, the initial level (2) is lower than the final level (4).

Hence energy is absorbed.

(b) n = 3 to n = 1

Here, the initial level (3) is higher than the final level (1).

Hence energy is released.

(c) n = 5 to n = 2

Here, the initial level (5) is higher than the final level (2).

Hence energy is released.

(d) n = 3 to n = 4

Here, the initial level (3) is lower than the final level (4).

Hence energy is absorbed.

The question is incomplete. Find the complete question here:

Which of these electron transitions correspond to absorption of energy and which to emission?

(a) n = 2 to n = 4

(b) n = 3 to n = 1

(c) n = 5 to n = 2

(d) n = 3 to n = 4

Learn more about electron transitions at brainly.com/question/2079874

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4 0
2 years ago
2. if 0.20 m fe3 had been used instead of 0.020 m fe3 , how would the numerical value of the rate constant and the activation en
dezoksy [38]

the calculated value is Ea is 18.2 KJ and A is 12.27.

According to the exponential part in the Arrhenius equation, a reaction's rate constant rises exponentially as the activation energy falls. The rate also grows exponentially because the rate of a reaction is precisely proportional to its rate constant.

At 500K, K=0.02s−1

At 700K, k=0.07s −1

The Arrhenius equation can be used to calculate Ea and A.

RT=k=Ae Ea

lnk=lnA+(RT−Ea)

At 500 K,

ln0.02=lnA+500R−Ea

500R Ea (1) At 700K lnA=ln (0.02) + 500R

lnA = ln (0.07) + 700REa (2)

Adding (1) to (2)

700REa100R1[5Ea-7Ea] = 0.02) +500REa=0.07) +700REa.

=ln [0.02/0 .07]

Ea= 2/35×100×8.314×1.2528

Ea =18227.6J

Ea =18.2KJ

Changing the value of E an in (1),

lnA=0.02) + 500×8.314/18227.6

= (−3.9120) +4.3848

lnA=0.4728

logA=1.0889

A=antilog (1.0889)

A=12.27

Consequently, Ea is 18.2 KJ and A is 12.27.

Learn more about Arrhenius equation here-

brainly.com/question/12907018

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5 0
1 year ago
Ice floats on the surface of water because ice is less dense than liquid water <br> true or false?
allsm [11]

Answer:

yes it is true.

Ice floats on the surface of water because ice is less dense than liquid water

Explanation:

4 0
3 years ago
Read 2 more answers
David found that water can be created in a lab by burning hydrogen gas in air. He concluded that water is not a compound because
Virty [35]

Hi~~

H2O, commonly known as water, is definitely a compound.

David's conclusion is wrong because the hydrogen gas combined with oxygen from the air to form dihydrogen monoxide, also known as water.


7 0
3 years ago
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