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3 years ago

How do you calculate the number of valence electrons in an atom?

1 answer:

5 0

To find the valence electrons in an atom, identify what group the element is in. An element in group 1A has 1 valence electron. For example, Li is in group 1A, so that means it has one valence electron. If the element is in group 2A, then it has two valence electrons.

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Pls answer ill give brainliest question in pic

RUDIKE [14]

C, im pretty sure if im wrong my bad

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2 years ago

How do metals form chemical bonds with other metals?

gogolik [260]

Answer:

Metallic bonding

Explanation:

Metals have low ionization energies. Therefore, their valence electrons are easily delocalized (attracted to the neighbouring metal atoms). These delocalized electrons are then not associated with a specific metal atom. Since the electrons are “free”, the metal atoms have become cations, and the electrons are free to move throughout the whole crystalline structure.

We say that a metal consists of an array of cations immersed in a sea of electrons .

The electrons act as a “glue” holding the cations together.

Metallic bonds are the attractive forces between the metal cations and the sea of electrons.

In an NaK alloy, for example, the Na and K atoms contribute their valence electrons to the "sea". The atoms aren’t bonded to each other, but they are held in place by the metallic bonding.

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2 years ago

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Geologists use the Law of Superposition to date rock layers. However, the Earth's

Allisa [31]

The answer is d faults

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2 years ago

Which process is a physical change? iron rusting milk turning into curd water boiling paper burning hard water stains pipes?

Elodia [21]

Iron rusting over is a physical change.

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3 years ago

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Valproic acid, used to treat seizures and bipolar disorder, is composed of C, H, and O. A 0.165 g sample is combusted to produce

mote1985 [20]

Answer:

The empirical formula is C₄H₈O;

The molecular formula is C₈H₁₆O₂.

Explanation:

The empiric formula is CxHyOz, and the combustion reaction occurs between the fuel and oxygen gas, so it will be:

CxHyOz + O₂ → CO₂ + H₂O

So, all the carbon will form CO₂ and all hydrogen will form H₂O. So, let's calculated the number of moles of carbon in CO₂ and the number of moles of hydrogen in H₂O. They must be the same number f the moles in the valproic acid.

The molar masses are: C= 12 g/mol, O = 156 g/mol and H = 1 g/mol, so CO₂ = 12 + 2x16 = 44 g/mol, and H₂O = 2x1 + 16 = 18 g/mol.

nCO₂ = 0.403/44 = 9.16x10⁻³ mol

In 1 mol of CO₂ there is 1 mol of C, so nC = 9.16x10⁻³ mol.

nH₂O = 0.166/18 = 9.22x10⁻³ mol.

In 1 mol of H₂O there are 2 moles of H, so nH = 0.018 mol.

The mass of Carbon and the mass of H in the compound must be:

mC = nxM = 9.22x10⁻³ x12 = 0.1106 g

mH = nxM = 0.018x1 = 0.018 g

The mass of oxygen must be then:

mC + mH +mO = 0.165

mO = 0.165 - 0.1106 - 0.018

mO = 0.0364g

And its number of moles:

nO = 0.0364/16 = 2.275x10⁻³ mol

To have the empirical formula, the coefficients must be the smallest, so let's divide the number of moles for the small one: 2.275x10⁻³

nC = (9.16x10⁻³ )/(2.275x10⁻³) = 4 mol

nH = 0.018/(2.275x10⁻³) = 8 mol

nO = (2.275x10⁻³)/(2.275x10⁻³) = 1 mol

The empirical formula is C₄H₈O.

The molecular formula must be a multiple of the empirical, so it will be n(C₄H₈O). Knowing the molar mass, we can calculate n:

4xnx12 + 8xnx1 + 1xnx16 = 144

48n + 8n + 16n = 144

72n = 144

n = 2

The molecular formula is 2(C₄H₈O) = C₈H₁₆O₂.

3 0

3 years ago