Do the boiling points and melting points of these elements support the claim that elements of the same group have similar physical characteristics?

Answer:

oxygen

Explanation:

Answer:

The number of protons and electrons are equal.

Explanation:

When an atom has an equal number of electrons and protons, it has an equal number of negative electric charges (the electrons) and positive electric charges (the protons). The total electric charge of the atom is therefore zero and the atom is said to be neutral.

Answer:

1g Hydrogen

Explanation:

Calcium in water reacts vigorously to give a cloudy white Precipitate (compound) called Calcium hydroxide alongwith the evolution of Hydrogen gas.

[tex] \boxed{ \mathsf{Ca + H_2O \rightarrow Ca(OH)_2 + H_2}}[/tex]

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This reaction is not in it's balanced form! The number of atoms of Hydrogen on the left is 2 while that on the right is 4,I.e.,they're not equal.

Adding a 2 in front of H2O solves the problem by making the number of atoms of each element on both the sides equal.

[tex] \mathsf{Ca +2 H_2O \rightarrow Ca(OH)_2 + H_2}[/tex]

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Looking into the equation more carefully, we see:

1 atom of Calcium reacts with 2 molecules of water to give 1 molecule of Calcium Hydroxide alongwith 1 molecule of Hydrogen gas.

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Mass of one atom of Calcium = it's gram atomic mass

= 40 g

Mass of one "molecule" of Hydrogen

= it's Gram molecular mass

= gram mass of one atom × number of atoms in one molecule

= 1 × 2

= 2 g

So,

according to our observation:

One atoms of Calcium gives one molecule of Hydrogen (during the particular reaction)

=> 40g of Calcium gives = 2g of Hydrogen

•°• 1 g of Calcium gives = [tex] \frac{2}{40} [/tex]

= [tex] \frac{1}{20} [/tex] g Hydrogen

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We're provided with 20g of Calcium,

=> 20g of Calcium gives = 20 × [tex] \frac{1}{20} [/tex] g H2

= 1 g H2

_______________

Hope this helps!

Answer:

true

Explanation:

because there is love in the universe and we converse in each others mind soul brain time stone

The answers to the questions are as follows;

Question 1:

Since Nitrogen has 5 Valence electrons, it needs 3 electrons to attain it's octet configuration. As such, it gains 3 electrons.

Question 2:

The quantity which determines how two atoms bond is The difference in their electronegativities.

Question 3:

This is because the elements have filled Valence levels.

Question 4:

The ion which has a stable Valence electron configuration is potassium (K) with a 1+ charge

Question 5;

The chemical formula which represents a polyatomic ion is; ClO-

Answer:

i think it's a sedimentary rock...

reason:- these are the only rocks containing fossils

Explanation:

brainliest plz

Answer:

A

Explanation:

Because it milliliter and litre is used to measure volume not meter or millimeter

Answer:

What are you a 6 yo? Anyways, the most common properties are, They are good conductors of electricity, They are lustrous and They are sonorous.

Answer:

the bond that forms between carbon and oxygen to create carbon dioxide

A polar covalent bond

Answer:

Freezing the liquid

Explanation:

Freezing a liquid causes a liquid to become a soild.

Answer:

changing the temperature of the liquid

Explanation:

Ex. Cooking brownie batter(liquid), turns it into an edible brownie(solid). Ex. Putting water into a freezer freezes it, turning it into a solid.

ANSWER : I AND III

HOPE IT HELPED

Answer:

They are not pure elements, instead they are compounds, hence why they are not found on the periodic table. (Periodic table only consists of pure elements)

Answer:

Dmitri Mendeleev

Explanation:

Answer:

The atomic number equals number of protons and electrons

This is true when an atom is in neutral state.

Explanation:

integral proteins...nns

Answer:

The water will eventually become the same temature (A)

Answer:

Below

Explanation:

The reaction is a Substitution SN1 mechanism

Answer:

Negatively charged ions are called anions, and an anion is formed when an atom gains an electron. Thus, the atom has an extra charge of electrons,

Explanation:

so it becomes negatively charged.

Negative ions (or anions) are atoms that have gained electrons.

Electrons have a negative charge so if an atom is getting more of them, it's becoming more negative.

Answer:4

Explanation:

The quantity of heat gained to raise the temperature from 25.0°C to 50.0°C is 10,450 Joules.

Given the following data:

To find the quantity of heat gained:

Mathematically, heat capacity or quantity of heat is given by the formula;

[tex]Q = mc\theta[/tex]

Where:

Substituting the values into the formula, we have:

[tex]Q = 100(4.18)(50 - 25)\\\\Q = 418(25)[/tex]

Quantity of heat = 10,450 Joules.

Read more: https://brainly.com/question/188778

Answer:

C. H:C:H:H

Explanation:

Follow these simple steps to correctly draw a Lewis dot structure: Add up the total number of valence electrons found in the entire compound. Draw the simple structure (skeleton structure) of the compound by connecting everything with single bonds only. Add electrons to all the noncentral atoms. Put any unused electrons on the central atom.

Answer:

unsafe, solar

Explanation:

A lunar eclipse covers the moon which is safe to look at. New Moon, again is simply the moon. However, we should never look at the sun, eclipsed or not!

Answer:

C, it is unsafe to view solar

without eye protection

Answer:

Chemical properties, such as combustibility, are generally observed as the identity of a substance changes and one or more new substances form.

Explanation:

Chemical change involves formation of new substances. Therefore, the correct answer is "Chemical properties, such as combustibility, are generally observed as the identity of a substance changes and one or more new substances form."

Answer:

D

Explanation:

Heterogeneous mixture is a mixture of non-uniform composition & in which the components can be easily identified

Answer:

Soil

Explanation:

Soil is made up of many things (therefore it's not pure) and does not appear to be uniform; it does not look the same throughout. Therefore it is heterogeneous.

Answer:

1 - B)    2 - B)     3 - A)

Explanation:

1. C3H8 + 5O2 → 3CO2 + xH2O.. Find 'X'.    

A) 3

B) 4

C) 5

D) 6

2. 4Al + 3O2 → xAl2O3. Find 'X'

A) 3

B) 2

C) 4

D) 5

3.  FeCl3 + 3NaOH → Fe(OH)3 + xNACl. Find 'x'

A)3

B) 4

C)5

D)6

More in Next Question...

Explanation: It is an alloy, very probable, not homogeneous.

                  A metal paper clip is usually steel, an alloy of iron, carbon, and other elements in various amounts.  A plastic paper clip is composed of a polymer, a very complex compound.

                   A paper clip is a Colloid

i guess this helped you pls mark me as brainliest

Answer:

I would assume its the last one "The grass in the prairie provides oxygen, while animals give off carbon dioxide gas."

Explanation:

The question asks how the animals and plants rely on each other

The plants provide oxygen and food for the animals, and the animals provide carbon dioxide to them.

Hope this helps :D

Answer:

d. compound

Explanation:

compound and elements are pure substances