Answer:
Se =[Ar] 3d¹⁰ 4s² 4p⁴
Explanation:
The noble gas notation is used for the shortest electronic configuration of other periodic table elements.
For example:
The atomic number of Argon is 18, and its electronic configuration is,
Ar₁₈ = 1s² 2s² 2p⁶ 3s² 3p⁶
The atomic number of selenium is 34, its electronic configuration is,
Se₃₄ = 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁴
By using the noble gas notation, electronic configuration of selenium can be written is shortest form.
Se =[Ar] 3d¹⁰ 4s² 4p⁴
This electronic configuration is also called abbreviated electronic configuration.
<span>protect it by covering it by lyophilic sol.</span>
1.Hans and Zacharias Janssen created the first microscope.
2.Robert Hooke was the first to use the word “cell.”
3.Anton van Leeuwenhoek observed small organisms he called “animalcules.”
4.Matthias Schleiden theorized that plants are made of cells.
5.Theodor Schwann theorized that animals are made of cells.
6.Rudolf Virchow theorized that cells come from other pre-existing cells.
The actual number of atoms of each element present in the molecule of the compound is represented by the formula known as molecular formula.
Molar mass of the unknown compound = 223.94 g/mol (given)
Mass of each element present in the unknown compound is determined as:
- Mass of carbon,
:

- Mass of hydrogen,
:

- Mass of chlorine,
:

Now, the number of each element in the unknown compound is determined by the formula:

- Number of moles of
:

- Number of moles of
:

- Number of moles of


Dividing each mole with the smallest number of mole, to determine the empirical formula:


Multiplying with 2 to convert the numbers in formula into a whole number:
So, the empirical formula is
.
Empirical mass = 
In order to determine the molecular formula:
n = 
n = 
So, the molecular formula is:

Distance traveled by the race horse=6 furlongs
Converting the distance from furlongs to rods: 40 rods =1 furlong

Converting the distance from rods to yards, feet and miles: 5.5 yards = 1 rod, 3foot =1 yard, 1 mile = 5280 feet.

The given speed of race horse = 40.7mi/hr
Calculating the time required:

Therefore, 66.34 s is required for a race horse to run six furlongs at 40.7 miles per hour.