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mezya [45]
3 years ago
8

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

Chemistry
1 answer:
gavmur [86]3 years ago
5 0
To find<span> the </span>valence electrons in an atom<span>, identify what group the element is in. An element in group 1A has 1 </span>valence electron<span>. For example, Li is in group 1A, so that means it has one </span>valence electron. If the element is in group 2A, then it has two valence electrons<span>.</span>
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Are there a 1000nm in a cm
Lynna [10]

Answer:

No

Explanation: There are 0.0001

4 0
3 years ago
____ 26. what is the weight percentage of nitrogen in urea, cn2h4o
Paraphin [41]
Weight percentage of nitrogen can be calculated using the following rule:
weight percentage of nitrogen = (weight of nitrogen / weight of urea) x 100

From the periodic table:
molecular mass of carbon = 12 grams
molecular mass of nitrogen = 14 grams
molecular mass of hydrogen = 1 grams
molecular mass of oxygen = 16 grams

therefore:
mass of nitrogen in urea = 2(14) = 28 grams
mass of urea = 12 + 2(14) + 4(1) + 16 = 60 grams

Substitute with the masses in the equation to get the percentage:
weight percentage of nitrogen = (28/60) x 100 = 46.667%
7 0
4 years ago
Which of the following is true of a compound but not a mixture? (1) A compound contains more than one element.
otez555 [7]

The composition of a compound does not vary because it is made up of fix ratio by mass.

<h3>What is compound?</h3>

A compound is a chemical substance that is composed of more than one element that held together by chemical bonds and produces fix ratio by mass so we can conclude that the composition of a compound does not vary because it is made up of fix ratio by mass.

Learn more about compound here: brainly.com/question/634206

7 0
2 years ago
Zat yang menunjukkan perubahan warna saat titk akhir titrasi tercapai
NikAS [45]
What language is that because I speak English
7 0
3 years ago
The carbon-carbon bond length in ethylene is ________ than the carbon-carbon bond length in ethane, and the HCH bond angle in et
tigry1 [53]

Answer:

shorter

longer

Explanation:

The carbon-carbon bond length in ethylene is <u>shorter</u> than the carbon-carbon bond length in ethane, and the HCH bond angle in ethylene is <u>longer</u> the HCH bond angle in ethane.

The objective of this question is to let us understand the concept of Bond Length and Bond angle among the unsaturated aliphatic hydrocarbons (i.e alkanes, alkenes and alkynes).

The variation in bond angles of  unsaturated aliphatic hydrocarbons  can be explained by two concepts; The valence shell electron pair repulsion (VSEPR) model and hybridization.

The VSEPR model determines the total number of electron pairs surrounding the central atom of a species. The total number of electron pairs  consist of the bond pairs and lone pairs. All the electron pairs( lie charge ) will then orient themselves in such a way to minimize the electrostatic repulsion between them.

As the number of the lone pairs increases from zero to 2 ; the bond angles diminish progressively.

However;

Hybridization is the mixing or blending of two or more pure atomic orbitals (s,p and d) to form two or more hybrid atomic orbitals that are identical in shape and energy . e.g sp, sp² , sp³  hybrid orbitals etc .

The shape of the geometry of this compound hence determines their bond  angle.

The shape of the geometry of ethane is tetrahedral which is 109.5° in bond angle while that of ethylene is trigonal planar which is 120°.

This is why the HCH bond angle in ethylene is longer  the HCH bond angle in ethane .

6 0
3 years ago
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