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3 years ago

How do we find the number of electrons in an atom?

Chemistry

1 answer:

Anon25 [30]3 years ago

5 0

I Believe this is the right answer:

Get a periodic table of elements. ...

Find your element on the periodic table. ...

Locate the element's atomic number. ...

Determine the number of electrons. ...

Look for the atomic mass of the element. ...

Subtract the atomic number from the atomic mass.

Hoped this helped!

You might be interested in

Phosphorus-32 has a half-life of 14.0 days. Starting with 6.00 g of 32P, how many grams will remain after 42.0 days ?

aleksandrvk [35]

6g...........3g..........1,5g........0,75g
0d..........14d.........28d.........42d

After 42 days 0,75g of Phoshorus-32 will remain.

4 0

2 years ago

Read 2 more answers

A 5.0L container is filled with H2 gas at STP. Predict what happens with the conditions of the gas change as described below (in

Amiraneli [1.4K]

Answer:

(a) As temperature increases, the average kinetic energy increases

(b) If H₂ is replaced with N₂, there will be increase in average velocity

(d) The increase in entropy as a result of an increase in temperature and average velocity will cause the kinetic energy to increase.

Explanation:

Given;

5.0L container filled with H₂ at stp

Part (a) What happens to average kinetic energy as temperature increases

As temperature increases, the average kinetic energy increases

Part(b) What happens to the average velocity if H₂ is replaced with N₂

Entropy is directly proportional to average velocity of gases and entropy increases with an increase in molecular mass.The molecular mass of nitrogen gas N₂ is greater than molecular mass of hydrogen gas H₂.

Thus, if H₂ is replaced with N₂, there will be increase in average velocity.

Part(c) What happens to the average velocity as temperature increases

Kinetic energy increases with an increase in temperature and average velocity.

An increase in temperature will cause increase in average velocity

Part (d) What happens to average kinetic energy if H₂ is replaced with N₂

The increase in entropy as a result of an increase in average velocity will cause the kinetic energy to increase.

3 0

2 years ago

Sodium acetate is produced by the reaction of baking soda and vinegar. The resultant solution is then heated until it becomes sa

user100 [1]

Answer: The thermal energy that would be released by 276.0g of sodium acetate trihydrate is 71.8kJ.

Explanation:

Supercooling is the process of lowering the temperature a liquid below its freezing point, without it becoming solid. A liquid below its freezing point will crystallize in the presence of a seed crystal because it serves as a structure for formation of crystals. From the question,

The given mass of sodium acetate trihydrate

(CH3COONa.3H2O)= 276.0g

Molar mass of sodium acetate

trihydrate= 136.08g/mol

Thermal heat of fusion of sodium acetate

trihydrate = 35.9 kJ/mol

From the given mass the number of moles present= 276.0/ 136.08

= 2.0moles

Therefore the heat (thermal) energy of the given mass of sodium acetate

trihydrate = 2.0 × 35.9

= 71.8kJ

Therefore, upon addition of a small seed crystal, the solution temperature increases as sodium acetate trihydrate crystallizes.

7 0

2 years ago

Will Mark Brainliest.

balandron [24]

Answer:

FeCl₃ . 6H₂O, BRAINLIST PLZ

Explanation:

1) The chemical formula of iron(III) chloride is FeCl₃ (the oxidation number of Fe is 3+, and the oxidation number of Cl is 1-).

2) The formula that you are lookin for the hydrate is of the type FeCl₃ . n H₂O, where n is the number of water molecules per each unit formula of Fe₂O₃.

3) Find the mass of anhydrous FeCl₃ by difference:

mass of FeCl₃ = mass of the sample - mass of the water in the sample

mass of FeCl₃ = 5.49g - 2.20 g = 3.29 g

4) Convert the mass of FeCl₃ in number of moles

number of moles = mass in grams / molar mass

molar mass of FeCl₃ = 55.845 g/mol + 3×35.453 g/mol = 162.204 g/mol

number of moles = 3.29 g / 162.204 g/mol = 0.0203 mol FeCl₃

5) Convert the mass of water in number of moles:

molar mass of water = 18.015 g/mol

number of moles of water = mass in grams / molar mass = 2.20 g / 18.015 g/mol = 0.122 moles H₂O

6) Find the mole ratio of water to iron chloride:

0.122 mol water / 0.0203 mol iron chloride = 6.01 ≈ 6

Therefore, the complete formula of the hydrate is FeCl₃ . 6H₂O,

4 0

2 years ago

A titanium cube contains 2.86×10^23 atoms. What is the edge length of the cube? The density of titanium is 4.50 g/cm^3. (The vol

Arada [10]

Answer: 1.72cm

Explanation:

First let us calculate the mass of titanium that contain 2.86×10^23 atoms..

1mole of a substance contains 6.02x10^23 atoms as we have come to understand from Avogadro's hypothesis. Therefore, 1mole of titanium also contains 6.02x10^23 atoms.

1mole of titanium = 48g

1mole (i.e 48g) of titanium contains 6.02x10^23 atoms,

Therefore Xg of titanium will contain 2.86×10^23 atoms i.e

Xg of titanium = (48x2.86×10^23)/6.02x10^23 = 22.8g

Next, we must find the volume of titanium

Density of titanium = 4.5g/cm^3

Mass of titanium = 22.8g

Volume =?

Density = Mass /volume

Volume = Mass /Density

Volume = 22.8/4.5

Volume = 5.07cm^3

Now we can find the edge length:

Volume = 5.07cm^3

Length =?

V = L^3

L = cube root (V)

L = cube root (5.07)

L = 1.72cm

6 0

3 years ago