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Alex777 [14]
2 years ago
6

Whic number of the periodic table is the atomic number and which number is the atomic mass?

Chemistry
1 answer:
Anettt [7]2 years ago
5 0

Answer:

The mass number (represented by the letter A) is defined as the total number of protons and neutrons in an atom. Consider the element helium. Its atomic number is 2, so it has two protons in its nucleus.

The atomic mass of a single atom is simply its total mass and is typically expressed in atomic mass units or amu. By definition, an atom of carbon with six neutrons, carbon-12, has an atomic mass of 12 amu.

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stealth61 [152]
So it’s OKAYYYYY ITS OKAYYYY
5 0
3 years ago
Give the number of protons, neutrons and electrons in 99Tc
miss Akunina [59]

Explanation:

Tc - 99 is technetium 99.

It is a radioactive element that decays spontaneously. It has a half-life of 211,000 years and decays to stable ruthenium.

  • On the periodic table, it has an atomic number of 43;

Mass number  = 99

Atomic number = number of protons = number of electrons in atom

  Number of protons in Tc is 43

                      electron is 43

Mass number = number of protons + number of neutrons

  Number of neutrons = mass number - number of protons = 99-43 = 56

learn more:

Atomic number brainly.com/question/2057656

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5 0
3 years ago
1. Show the mechanism for the main product for the monochlorination of 2-methylbutane. List all other products.
Bad White [126]

Answer:

See explanation below

Explanation:

First, we need to understand that the monochlorination of an alkane like this one, involves substitution of one of the atoms of hydrogen of the molecule for an atom of chlorine.

This reaction takes place when the alkane reacts with Cl₂ in presence of light or heat.

When this happens, the first step involves the breaking of the double bond of the chlorine to form the ion Cl⁻.

The next step involves the substraction of the hydrogen of the molecule by the Chlorine. This will leave the alkane with a lone pair available for reaction.

The third step, the alkane with the lone pair of electron substract a chlorine for the beggining and form the mono chlorinated product.

The final step involves forming the remaining products with the remaining reagents there.

In the picture attached you have the mechanism and product for this reaction:

3 0
3 years ago
Read 2 more answers
An asteroid in space has traveled 4,500 km in 60 s, what is the average speed of the asteroid?
weqwewe [10]
The average speed is 75 Km per hour. Remember the equation for speed is Speed = Distance divided by Time
6 0
3 years ago
The rate law for the decomposition of phosphine () is It takes 135. s for 1.00 M to decrease to 0.250 M. How much time is requir
vova2212 [387]

Answer:

189.71 secs

Explanation:

We know that decomposition is a first order reaction;

So;

ln[A] = ln[A]o - kt

But;

[A]o = 1.00 M

[A] = 0.250 M

t =135 s

Hence;

ln[A] -  ln[A]o = kt

k = ln[A] -  ln[A]o/t

k = ln(1) - ln(0.250)/135

k =0 - (-1.386)/135

k = 1.386/135

k= 0.01

So time taken now will be;

ln[A] -  ln[A]o = kt

t = ln[A] -  ln[A]o/k

t = ln (3) - ln(0.450)/0.01

t = 1.0986 - (-0.7985)/0.01

t = 1.0986 + 0.7985/0.01

t = 189.71 secs

8 0
2 years ago
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