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dimaraw [331]
2 years ago
7

How do you determine how many neutrons an element has?

Chemistry
1 answer:
Alexandra [31]2 years ago
4 0

Answer:

To find the number of neutrons, subtract the number of protons from the mass number. number of neutrons

Explanation:

You might be interested in
(a) Compute the radius r of an impurity atom that will just fit into an FCC octahedral site in terms of the atomic radius R of t
11Alexandr11 [23.1K]

Answer:

a

The radius of an impurity atom occupying FCC octahedral site is 0.414{\rm{R}}

b

The radius of an impurity atom occupying FCC tetrahedral site is 0.225{\rm{R}} .

Explanation:

In order to get a better understanding of the solution we need to understand that the concept used to solve this question is based on the voids present in a unit cell. Looking at the fundamentals

An impurity atom in a unit cell occupies the void spaces. In FCC type of structure, there are two types of voids present. First, an octahedral void is a hole created when six spheres touch each other usually placed at the body center. On the other hand, a tetrahedral void is generated when four spheres touch each other and is placed along the body diagonal.

Step 1 of 2

(1)

The position of an atom that fits in the octahedral site with radius \left( r \right)is as shown in the first uploaded image.

In the above diagram, R is the radius of atom and a is the edge length of the unit cell.

The radius of the impurity is as follows:

2r=a-2R------(A)

The relation between radius of atom and edge length is calculated using Pythagoras Theorem is shown as follows:

Consider \Delta {\rm{XYZ}} as follows:

(XY)^ 2 =(YZ) ^2 +(XZ)^2

Substitute XY as{\rm{R}} + 2{\rm{R + R}} and {\rm{YZ}} as a and {\rm{ZX}} as a in above equation as follows:

(R+2R+R) ^2 =a ^2 +a^ 2\\16R ^2 =2a^ 2\\ a =2\sqrt{2R}

Substitute value of aa in equation (A) as follows:

r= \frac{2\sqrt{2}R -2R }{2} \\ =\sqrt{2} -1R\\ = 0.414R

The radius of an impurity atom occupying FCC octahedral site is 0.414{\rm{R}}

Note

An impure atom occupies the octahedral site, the relation between the radius of atom, edge length of unit cell and impure atom is calculated. The relation between the edge length and radius of atom is calculated using Pythagoras Theorem. This further enables in finding the radius of an impure atom.  

Step 2 of 2

(2)

The impure atom in FCC tetrahedral site is present at the body diagonal.

The position of an atom that fits in the octahedral site with radius rr is shown on the second uploaded image :

In the above diagram, R is the radius of atom and a is the edge length of the unit cell.

The body diagonal is represented by AD.

The relation between the radius of impurity, radius of atom and body diagonal is shown as follows:

AD=2R+2r----(B)

   In    \Delta {\rm{ABC}},

(AB) ^2 =(AC) ^2 +(BC) ^2

For calculation of AD, AB is determined using Pythagoras theorem.

Substitute {\rm{AC}} as a and {\rm{BC}} as a in above equation as follows:

(AB) ^2 =a ^2 +a ^2

AB= \sqrt{2a} ----(1)

Also,

AB=2R

Substitute value of 2{\rm{R}} for {\rm{AB}} in equation (1) as follows:

2R= \sqrt{2} aa = \sqrt{2} R

Therefore, the length of body diagonal is calculated using Pythagoras Theorem in \Delta {\rm{ABD}} as follows:

(AD) ^2 =(AB) ^2 +(BD)^2

Substitute {\rm{AB}} as \sqrt 2a   and {\rm{BD}} as a in above equation as follows:

(AD) ^2 =( \sqrt 2a) ^2 +(a) ^2 AD= \sqrt3a

For calculation of radius of an impure atom in FCC tetrahedral site,

Substitute value of AD in equation (B) as follows:

\sqrt 3a=2R+2r

Substitute a as \sqrt 2{\rm{R}} in above equation as follows:

( \sqrt3 )( \sqrt2 )R=2R+2r\\\\

r = \frac{2.4494R-2R}{2}\\

=0.2247R

\approx 0.225R

The radius of an impurity atom occupying FCC tetrahedral site is 0.225{\rm{R}} .

Note

An impure atom occupies the tetrahedral site, the relation between the radius of atom, edge length of unit cell and impure atom is calculated. The length of body diagonal is calculated using Pythagoras Theorem. The body diagonal is equal to the sum of the radii of two atoms. This helps in determining the relation between the radius of impure atom and radius of atom present in the unit cell.

7 0
3 years ago
What’s the answer ?
Romashka-Z-Leto [24]

Answer:

45.3°C

Explanation:

Step 1:

Data obtained from the question.

Initial pressure (P1) = 82KPa

Initial temperature (T1) = 26°C

Final pressure (P2) = 87.3KPa.

Final temperature (T2) =.?

Step 2:

Conversion of celsius temperature to Kelvin temperature.

This is illustrated below:

T(K) = T(°C) + 273

Initial temperature (T1) = 26°C

Initial temperature (T1) = 26°C + 273 = 299K.

Step 3:

Determination of the new temperature of the gas. This can be obtained as follow:

P1/T1 = P2/T2

82/299 = 87.3/T2

Cross multiply to express in linear form

82 x T2 = 299 x 87.3

Divide both side by 82

T2 = (299 x 87.3) /82

T2 = 318.3K

Step 4:

Conversion of 318.3K to celsius temperature. This is illustrated below:

T(°C) = T(K) – 273

T(K) = 318.3K

T(°C) = 318.3 – 273

T(°C) = 45.3°C.

Therefore, the new temperature of the gas in th tire is 45.3°C

6 0
3 years ago
Which of the following information can be determined from this isotope: sodium 23 and why?
JulsSmile [24]

<h2>YOUR ANSWER Is number of istopes</h2>

✌️

4 0
2 years ago
"how a trait appears, or is physically expressed?
grin007 [14]
I think the answer is genotype.
6 0
2 years ago
How many protons, electrons and neutrons are in the isotope 13C ?
Vadim26 [7]

Hey there!

We can tell from the information we are given that the sum of protons and neutrons is 13, there is 6 protons since it is a carbon atom, and there is no charge which means the number of protons is equal to the number of electrons.

6 + n = 13

n = 7

The number of protons is equal to the number of electrons, so there is 6 electrons.

The isotope 13C has 6 protons, 6 electrons, and 7 neutrons.

Hope this helps!

7 0
2 years ago
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