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4 years ago

Which statements about the structure of the periodic table are true?

Chemistry

1 answer:

DiKsa [7]4 years ago

3 0

Answer:

The distribution of electrons in energy levels is responsible for the shape of the periodic table.

Explanation:

Henry Moseley in the 1900s re-stated the periodic law by changing the basis of the table to reflect more on the atomic number. The present law is therefore "the properties of elements are a periodic function of their atomic numbers".

Atomic number is the number of electrons in an atom and it is the same as the number of protons for neutral atoms.

In the table, elements having the same number of electrons in the outermost shell of their atoms are placed over one another in vertical columns. Each of the vertical column is known as a group or family while each of the resulting horizontal rows is known as period or row.

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Given the following reaction:

babunello [35]

Answer:

1234.0

Explanation:

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3 years ago

Which of the following is not a part of Dalton’s atomic theory?

yaroslaw [1]

The answer is C. Atoms are always in motion.

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3 years ago

Read 2 more answers

Which object is a good conductor of heat and electricity?

Alex

Answer:

Explanation:

Metals are good conductors of heat

8 0

3 years ago

Calculate the freezing point of a solution that contains 8.0 g of sucrose (c12h22o11) in 100 g of h2o. kf for h2o = 1.86c/m

Sever21 [200]

Answer is: the freezing point of the solution of sucrose is -0.435°C.
m(H₂O) = 100 g ÷ 1000 g/kg = 0.1 kg.
m(C₁₂H₂₂O₁₁) = 8.0 g.
n(C₁₂H₂₂O₁₁) = m(C₁₂H₂₂O₁₁) ÷ M(C₁₂H₂₂O₁₁).
n(C₁₂H₂₂O₁₁) = 8.0 g ÷ 342.3 g/mol.
n(C₁₂H₂₂O₁₁) = 0.0233 mol.
b(solution) = n(C₁₂H₂₂O₁₁) ÷ m(H₂O).
b(solution) = 0.0233 mol ÷ 0.1 kg.
b(solution) = 0.233 m.
ΔT = b(solution) · Kf(H₂O).
ΔT = 0.233 m · 1.86°C/m.
ΔT = 0.435°C.
Tb = 0°C - 0.435°C = -0.435°C.

3 0

3 years ago

Why are the concentrations of [H3O+] and [OH−] equal in pure water?

kotegsom [21]

Answer : The correct option is, (A) $[H_3O^+]=[OH^-]$ because one of each is produced every time an $[H^+]$ transfers from one water molecule to another.

Explanation :

As we know that, when the two water molecule combine to produced hydronium ion and hydroxide ion.

The balanced reaction will be:

$HOH+HOH\rightarrow H_3O^++OH^-$

Acid : It is a substance that donates hydrogen ion when dissolved in water.

Base : It is a substance that accepts hydrogen ion when dissolved in water.

From this we conclude that, the hydrogen ion are transferred from one water molecule to the another water molecule to form hydronium ion and hydroxide ion. In this reaction, one water molecule will act as a base and another water molecule will act as an acid.

Hence, the correct option is, (A)

3 0

4 years ago