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3 years ago

In which of the following atoms are valence electrons in the lowest average potential energy states?

Chemistry

1 answer:

Andrej [43]3 years ago

7 0

Answer:

C) F

Explanation:

Valence electrons are the electrons present in the outermost shell of an atom and have the highest energy level of an atom whereas electrons at ground state or lower orbitals have less potential energy.

This is so because <u>orbitals nearby nucleus are strongly bonded with the atomic nucleus and have less energy than an outermost shell.</u>

So, the potential energy states of an atom depend on the number of orbitals. In the given options fluorine with atomic number 9 has less number of orbitals that is 2 orbitals and valence electrons will be present in second orbitals, so fluorine will have the lowest average potential energy states.

Hence, the correct option is "C) F".

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A flask contains oxygen, carbon dioxide,

Grace [21]

Answer:

The total pressure is 25.7 atm

Explanation:

The total pressure is the sum of the pressures of the three gases in the flask.

total pressure=(11.4+5.6+8.7) atm

=25.7 atm

8 0

3 years ago

What three (3) factors determine the reactivity of elements? Explain and give examples of each.

Degger [83]

Explanation:

The three factors which determine the reactivity of elements are as follows.

(1) Number of valence electrons.

(2) Size of an atom.

(3) Electro negativity of an atom.

All these factors are explained as follows.

(1) Number of valence electrons

According to the octet rule, every atom requires to attain stability. Therefore, number of electrons in the outermost shell will decide the reactivity of an atom as every atom needs to fill its shells or sub shells as per the octet rule. As a result, the reactivity increases.

For example, the atomic number of chlorine is 17 and its electronic configuration is $1s^{2}2s^{2}2p^{6}3s^{2}3p^{5}$

In the 3p sub shell, there is deficiency of one electron. So, in order to attain stability chlorine atom will react readily with another species or atom which can either donate or share one electron.

Whereas an atom with completely fill shell will have low reactivity.

(2) Size of an atom

On moving down the group size of atom increases. As a result, the attraction between the nucleus and electrons decreases due to the shielding effect. Thus, the larger is an atom, the more easily it can give electrons. Therefore, the reactivity increases.

For example, the atomic number of calcium is 20 and its electronic configuration is $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}$

Also it is known that first shell of every atom can have 2 electrons, second shell can have 8 electrons, third shell can have 18 electrons and so on.

Since, calcium is larger in size as compared to beryllium and magnesium so it will readily loose 2 electrons to attain stability. Thus, it will attain a $Ca^{2+}$ charge.

(3) Electro negativity of an atom

An atom with uneven distribution of electrons will acquire a certain amount of charge. Thus, it becomes polar in nature and in order to gain stability, the atom will either loose or gain electrons according to its charge.

For example, atomic number of fluorine is 9 and its electronic configuration is $1s^{2}2s^{2}2p^{5}$ .

So, in order to gain stability fluorine will readily accept 1 electron to completely fill its 2p sub shell. As a result, the electronic configuration will become $1s^{2}2s^{2}2p^{6}$

Therefore, fluorine will have a charge of -1 because it has gained one electron.

3 0

3 years ago

Calculate the number of oxygen atoms in a 140,0 g sample of fron(III) oxide (Fe, 0).

Elodia [21]

Answer:

7.951 x 0²³atoms

Explanation:

Mass of Fe₃O₄ = 140g

Solution:

To find the number of oxygen atoms in iron(III) oxide, we first find the number of moles in the compound:

Number of moles = $\frac{mass}{molar mass}$

Molar mass of Fe₃O₄ = (3x56) + (4x64) = 168 + 256 =424g/mol

Number of moles = $\frac{140}{424}$ = 0.33mole

1 mole of an atom contains 6.02 x 10²³atoms

∴number of oxygen atoms in Fe₃O₄ = 4 x 0.33 x 6.02 x 10²³atoms

= 7.951 x 0²³atoms

4 0

4 years ago

Determine the temperature change when a 100. g block of gold is supplied with 1.00 x 103 J of heat will give brainliest pls help

rusak2 [61]

Answer:

77.5°C

Explanation:

Data obtained from the question include the following:

Mass (M) = 100g

Heat (Q) = 1x10^3 J

Change of temperature (ΔT) =..?

Note: The specific heat capacity (C) of gold = 0.129 J/g°C

With the above information obtained from the question, we can obtain the change in temperature as follow:

Q = MCΔT

Divide both side by MC

ΔT = Q/MC

ΔT = 1x10^3 / (100 x 0.129)

ΔT = 77.5°C

Therefore, the change in temperature is 77.5°C

5 0

3 years ago

Which species has the shortest carbon-nitrogen bond, CH3CN, CH3NH2, or CH2NH? acetonitrile methylamine methanimine (c) Which spe

Arturiano [62]

Answer:

Shortest carbon-nitrogen bond = CH3CN, strongest carbon-nitrogen bond = CH3CN

Explanation:

Bond length is defined as the distance between the centers of two covalently bonded atoms, in this case; carbon and hydrogen.

The length of the bond is determined by the number of bonded electrons (the bond order).

The higher the bond order, the stronger the pull between the two atoms and the shorter the bond length.

Therefore, bond length increases in the following order: triple bond < double bond < single bond.

CH3CN - There's a triple bond between Carbon and Nitrogen

CH3NH2 - The bond between carbon and nitrogen is a single bond.

CH2NH - The bond between carbon and nitrogen is a double bond.

The specie with the shortest carbon-nitrogen bond is CH3CN (acetonitrile).

The species with the strongest carbon-nitrogen bond is also CH3CN (acetonitrile) because it contains a triple bond. A triple bond contains one sigma and 2 pi bonds. The energy required to break it is more when compared to the other bonds hence, it is the strongest bond.

6 0

3 years ago