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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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What most likely occurred during this demonstration?
Katena32 [7]

Answer:

Hydrogen gas and a salt formed at the end of the reaction.

Explanation:

Hydrogen Gas has formed which inflated the balloon

Usually, metals and acids react to form a salt and Hydrogen Gas.

Here's what happened:

Zn (s) + 2HCl (aq) →  ZnCl_2(aq) +H_2(g)

Cheers :)

7 0
3 years ago
A species with a charge of -1 contains 57 electrons and 80 neutrons. What is the identity of the species. Note: The species show
Inga [223]

In a neutral atom, the number of protons is equal to the number of electrons.

Given that the charge on the ion of the element is -1. This means that there is one electron more than the number of protons in the element.

The atomic number = Number of protons = 57 -1 = 56

Element with atomic number 56 is Barium.

Mass number of the element = Number of protons + Number of neutrons

                                                = 56 + 80 = 136

So the identity of the species: ^{136}Ba^{-}

3 0
3 years ago
Oxygen gas can be prepared by heating potassium chlorate according to the following equation:
Cerrena [4.2K]

Moles KClO₃ = 0.239

<h3>Further explanation</h3>

Given

Reaction

2KClO₃(s) ⇒2KCl(s) + 3O₂(g)

P water = 23.8 mmHg

P tot = 758 mmHg

V = 9.07 L

T = 25 + 273 = 298 K

Required

moles of KClO₃

Solution

P tot = P O₂ + P water

P O₂ = P tot - P water

P O₂ = 758 - 23.8

P O₂ = 734.2 mmHg = 0.966 atm

moles O₂ :

n = PV/RT

n = 0.966 x 9.07 / 0.082 x 298

n = 0.358

From equation, mol ratio KClO₃ : O₂ = 2 : 3, so mol KClO₃ :

= 2/3 x mol O₂

= 2/3 x 0.358

= 0.239

4 0
3 years ago
During an investigation a scientist burned 48 g of magnesium strip. After the reaction the total mass of the product formed was
ddd [48]

Answer:

The law of conservation of mass applies to both cases

      When 50 g of sugar undergoes a physical change, say for example  melting, the amount of sugar in the solution or melted form will also be 50 grams. This shows that the mass before and after the change was the same, in accordance to the law of conservation of mass. The mass stays the same.

When the magnesium strip is burned, this is a chemical reaction. The problem is that we only measure the mass of one of the substances involved in the reaction which is the magnesium strip, which makes it seem like the mass has increased. Actually, while burning, the magnesium combines with oxygen in the air. This oxygen was present before the reaction, we just did not measure it. And after the reaction it is present in the form of product. But the mass is still conserved.

Hope this helps!!:)

4 0
3 years ago
Read 2 more answers
Which of the following is a measure of randomness in a system?
vitfil [10]

Answer:

A) entropy

Explanation:

4 0
3 years ago
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