Dalton's atomic theory stated?

1 answer:

3 0

John Dalton in d year 1808 proposed d atomic theory.. 1.All elements are made up of small, indivisble particles called atoms. 2.Atoms can neither be created nor destroyed. 3.Atoms of d same element are alike in every aspect, &differ from atoms of all other elements. 4. When atoms combine with other atoms, they do so in simple ratios.

You might be interested in

Which of the following isoelectronic series is correctly ranked from largest ionic radius to smallest ionic radius? 1. N 3−, O 2

love history [14]

Answer:

Option 1: N⁻³ > O⁻² > F⁻ > Na⁺ > Mg⁺²

Explanation:

Ionic radius is the radius of an atom´s ion in ionic crystal structure. In an ion that lose an electron, to form a cation, the radius of the ion gets smaller, because the repulsion between electrons decrease because fewer electrons are present. Conversely, adding on electron to a neutral atom, to form an anion, causes electron - electron repulsions to increase, so the size of the radius of the ion gets bigger.

Isoelectronic species are ions or elements that have the same number of electrons in their electronic shells but have different overall charges, because of their different atomic numbers.

In a isolelectronic series (same number of electrons), the increase of the positive charge (given by the number of protons in the nucleus), will cause a decrease in radius beacuse the greater electrostatic attraction between the electrons and the nucleus. Consequently, the ion with the greatest nuclear charge will have the smallest ionic radius and the ion with the smallest nulear charge will have the largest ionic radius.

We will use this principle to solve our problem.

In our case, the given ions are:

N⁻³ : Z = 7, e⁻ = 10
O⁻²: Z= 8, e⁻ =10
F⁻: Z = 9, e⁻ = 10
Na⁺: Z= 11, e⁻ = 10
Mg⁺²: Z=12, e⁻ =10

where Z= number of protons, and e⁻ = number of electrons.

Hence the decreasing order of ionic radius is:

N⁻³ > O⁻² > F⁻ > Na⁺ > Mg⁺²

Have a nice day!

4 0

2 years ago

How does air above a heated surface move?

anzhelika [568]

When air is warmed up, its molecules move faster and faster and as a result they move further from each other. They still have the same mass, but they now occupy a larger volume. This means that its density is smaller.
The opposite when air is cooled off. The molecules slow down, get closer together, occupy a smaller volume and therefore its density is bigger.

When air is warmed up, it goes up. Once it's up there, is cools off and goes back down. Near the heated surface the air gets warmed up again, goes up, cools down, goes back down, and again and again.
that is called convection cells

6 0

2 years ago

Question 7 unsaved liquid water can store more heat energy than an equal amount of any other naturally occurring substance becau

Paul [167]

Has the highest specific heat.
___________

3 0

3 years ago

Please help me with these two questions

ANEK [815]

What is the question?

8 0

2 years ago

Antifreeze is mixed with water in a car's cooling system because the solution what?

Nikolay [14]

Antifreeze is an additive in water-based liquid to lower down the freezing point of such liquid. It is used to make use of the colligative properties of solutions specifically freezing-point depression for cold climate and boiling-point elevation to allow higher coolant temperature.

8 0

3 years ago