Hydrogen, helium and oxygen
If you spill a chemical on you, you should call poison control or 911
Answer:
Rubidium (Rb).
Explanation:
From the question given above, the following data were obtained:
Electronic configuration => 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s¹
Name of element =?
To know the name of the element with the above electronic configuration, we shall determine the atomic number of the element. This can be obtained as follow:
Number of electrons = 2 + 2 + 6 + 2 + 6 + 2 + 10 + 6 + 1
Number of electrons = 37
Next, we shall determine the number of protons. This can be obtained as follow:
From the question given above, the element has no charge. Hence the element contains equal numbers of protons and electrons.
Number of electrons = 37
Number of protons = number of electrons = 37
Next, we shall determine the atomic number. This can be obtained as follow:
The atomic number of an element is simply defined as the number of protons present in the atom of the element. Thus,
Atomic number = proton number
Proton is = 37
Therefore,
Atomic number = 37
Finally, we shall determine the name of the element by comparing the atomic number of those in the periodic table.
Thus, the element with the above electronic configuration is Rubidium (Rb) since no two elements have the same atomic number
The mass percentage of KCl solution is 21.34%
Calculation,
Given molality of KCl aqueous solution = 3. 64 m = 3. 64 mole/ Kg
It means 3. 64 mole of solute present in 1Kg of solvent
or , 3. 64 mole of solute present in 1000 g of solvent ( water )
Mass of solute ( KCl ) = 3. 64 mole×74.55 g/mole =271.3 g
The total mass of solution ( KCl + water ) = 271.3 g + 1000 g = 1271.3 g
Mass percentage is equal to percentage of mass of solute present in total mass of solution.
Mass percentage = 100×271.3 g/1271.3 g = 21.34%
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