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4 years ago

How does the number of valence electrons in an atom relate to the elements placement on the periodic table?

1 answer:

8 0

If the number of valence electron is one than it will be placed in group IA. elements of group IIA will have two valence electrons and so on....

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BRAINIEST TO THE ONE WHO ANSWER THIS

alexandr1967 [171]

Answer:

The statement that best describes the trend in first ionization enery of elements on the periodic table is:

It generally decreases down a group because valence electrons are farther from the nucleus.

The first ionization energy measures how difficult is to release an electron from the outermost shell. The higher the ionization energy the more difficult it is to release an electron, the lower the ionication energy the easier to release an electron.

As the atomic number of the atom increases (which is what happens when you go down a group) the furthest the outermost shell of electrons will be (the size of the atoms increases) and so those electrons require less energy to be released, which means that the ionization energy decreases.

Hope it helps!

4 0

3 years ago

Read 2 more answers

The decomposition of dinitrogen pentaoxide has an activation energy of 102 kJ/mol and ΔH°rxn = + 55 kJ/mol. What is the activati

ahrayia [7]

Answer: The activation energy of the reverse reaction is 47 kJ/mol

Explanation:

The chemical equation for the decomposition of dinitrogen pentaoxide follows:

$N_2O_5\rightleftharpoons 2NO_2+\frac{1}{2}O_2$

We are given:

Activation energy of the above reaction (forward reaction) = 102 kJ/mol

Enthalpy of the reaction = +55 kJ/mol

As, the enthalpy of the reaction is positive, the reaction is said to be endothermic in nature.

To calculate the activation energy for the reverse reaction, we use the equation:

$E_a_{\text{(forward)}}=E_a_{\text{(backward)}}+|\Delta H|$

where,

$E_a_{\text{(forward)}}$ = Activation energy of the forward reaction = 102 kJ/mol

$E_a_{\text{(backward)}}$ = Activation energy of the backward reaction = ?

$\Delta H$ = Enthalpy of the reaction = +55 kJ/mol

Putting values in above equation, we get:

$102=E_a_{\text{(backward)}}+55\\\\E_a_{\text{(backward)}}=(102-55)=+47kJ/mol$

Hence, the activation energy of the reverse reaction is 47 kJ/mol

3 0

3 years ago

A chunk of ice breaks off a glacier and falls 30.0 m before it hits the water. Assuming it falls freely (there is no air resista

lina2011 [118]

Answer:

The ice chunk will take 2.47 seconds to hit the water.

Explanation:

Height from which ice chunk fell = h = 30.0 m

Initial velocity of the ice chunk = u = 0 m/s

Time taken by ice chunk to cover 30.0 m of height = t

Acceleration due to gravity = g $9.8m/s^2$

Using second equation of motion ;

$h=ut+\frac{1}{2}gt^2$

$30.0 m=0 m/s\times t+\frac{1}{2}\times 9.8 m/s^2\times t^2$

$t=\sqrt{\frac{30.0m/s\times 2}{9.8 m/s^2}}2.47 s$

The ice chunk will take 2.47 seconds to hit the water.

7 0

3 years ago

Question 13 What is the base name for the following compound? C-C=0

White raven [17]

Explanation:

What is the base name for the following compound? C-C=0. Add answer+5 pts. Log in to add comment.

7 0

3 years ago

You can obtain a rough estimate of the size of a molecule with the following simple experiment: Let a droplet of oil spread out

mina [271]

Answer:

The diameter of the oil molecule is $4.4674\times 10^{-8} cm$ .

Explanation:

Mass of the oil drop = $m=9.00\times 10^{-7} kg$

Density of the oil drop = $d=918 kg/m^3$

Volume of the oil drop: v

$d=\frac{m}{v}$

$v=\frac{m}{d}=\frac{9.00\times 10^{-7} kg}{918 kg/m^3}$

Thickness of the oil drop is 1 molecule thick.So, let the thickness of the drop or diameter of the molecule be x.

Radius of the oil drop on the water surface,r = 41.8 cm = 0.418 m

1 cm = 0.01 m

Surface of the sphere is given as: a = $4\pi r^2$

$a=4\times 3.14\times (0.418 m)^2=2.1945 m^2$

Volume of the oil drop = v = Area × thickness

$\frac{9.00\times 10^{-7} kg}{918 kg/m^3}=2.1945 m^2\times x$

$x= 4.4674\times 10^{-10} m= 4.4674\times 10^{-8} cm$

The thickness of the oil drop is $4.4674\times 10^{-8} cm$ and so is the diameter of the molecule.

6 0

3 years ago