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3 years ago

Which statement about the elements in the periodic table is true

Chemistry

2 answers:

miss Akunina [59]3 years ago

8 0

Answer:

The reactivity of alkali metals increases as atomic mass increases.

Explanation:

There are six elements in the periodic table that can be classified as alkali metals. These elements are extremely reactive and it is correct to say that the reactivity of alkali metals increases as the atomic mass increases.

These metals can be found in the IA family of the periodic table and contain the names: Lithium, Sodium, Potassium, Rubidium, Cesium, Francium.

egoroff_w [7]3 years ago

6 0

A. The number of valence electrons increases as atomic mass increases. == Generally true for the representative elements since atomic mass generally increases with increasing Z.

B. The reactivity of alkali metals increases as atomic mass increases. == True. Atomic mass increases down the column and so does reactivity

C. The reactivity of the halogens increases as atomic mass increases. == False. Reactivity decreases down the column.

D. The number of valence electrons decreases across a period. == False. In general, the number of valence electrons increases across a period, particularly for the representative elements.

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Which of the following is not true? a. The freezing point of sea water is lower than the freezing point of pure water. b. The bo

Anna007 [38]

Answer:

The false statement is b.

The boiling point of a water sample from the Salt Lake is lower than the boiling point of pure water

Explanation:

This excersise refers to colligative properties.

Boiling point refers to the property of boiling point elevation. In a solution of ions, as water sea or water from lakes, the boiling point will be higher than water pure.

It is logical to say that, because these sort of water have ions. Remember that colligative properties depends on the solute particles.

T° boiling solution - T° pure solvent = Kb . m . i

In the freezing point depression, we have the oppossite of boiling point elevation. Freezing point of solution is lower than pure solvent, according to this:

T° freezing pure solvent - T° freezing solution = Kc . m . i

We have to always consider the i, which means Van't Hoff factor, number of ions dissolved in solution. As the i is higher, the freezing point of solution will be lower, and the boiling point of solution will be higher.

They are true statement a and c.

In solution of., [NaCl] = 0.1M, as it is a higher concentration, the molality is also higher than a solution of [NaCl] = 0.05.

As water sample form Salt Lake has certain ions, it is logical to say that the boiling point of this water is higher than boiling point of pure water.

5 0

3 years ago

I've asked before and gotten spammed hopefully I won't get spammed this time please help me with this someone. pls help anyonw

elena55 [62]

Answer:

See below!

Explanation:

A. The picture of the graph is attached. You can tell the amount of protons in an element by looking at the periodic table. The elements are ordered by the number of protons in an element.

B. Carbon and silicon are at the peaks of the chart. The peak is the highest point in a graph.

C. The elements belong to the non-metal group.

D. The halogens are non-metals, and their vapors are colorless.

The halogens are toxic to humans.

Halogen molecules are made of two atoms; they are diatomic.

Halogens react with non-metals to form crystalline compounds that are salts.

The halogens get less reactive going down the group on the periodic table.

Halogens can bleach vegetable dyes and kill bacteria.

E. The picture of the table is attached. To figure which numbers to put where, you need to pay attention to the other numbers. The halogens follow a trend with each of these properties. You have to put in the numbers that fit in among the other numbers.

3 0

3 years ago

Write an equation that shows the formation of the chloride ion from a neutral chlorine atom

jeka57 [31]

The gaining of electron by an atom results in the formation of anion shown by the negative charge on the atom whereas lose of electron results in the formation of cation shown by positive charge on the atom. The atom lose or gain electron to complete their octet and get stable in nature.

The chlorine atom will gain an electron and form chloride anion with one negative charge on it. The chloride ion is more stable in nature compared to the chlorine atom due to complete octet of chloride ion by gaining of electron.

Electronic configuration of chlorine atom is:

$[Ne]3s^{2}3p^{5}$

By gaining of one electron, electronic configuration of chloride ion is:

$[Ne]3s^{2}3p^{6}$

Thus, the equation that shows the formation of the chloride ion from a neutral chlorine atom is:

$Cl+1e^{-}\rightarrow Cl^{-}$

4 0

3 years ago

Which of the following statements is true?

k0ka [10]

The second and first one but if it isn’t 2 choices then 1

4 0

3 years ago

A genetic mutation is always observable in an organism physical appearance True or false

ale4655 [162]

Answer:

false

Explanation:

false, only a small percentage of mutations cause genetic disorders—most have no impact on health or development. For example, some mutations alter a gene's DNA sequence but do not change the function of the protein made by the gene.

4 0

3 years ago