Mary thinking her astrological sign, Leo, is a perfect fit for her personality is a belief in pseudoscience because there is not scientific evidence confirming such beliefs.
The answer is the second option.
Answer:
A)21
Explanation:
To know the difference between the number of electrons in the two atoms, we must first know the number of electrons in the atoms.
For Selenium, Se, we have 34 electrons. The element is in group 6 on the periodic table.
Aluminum on the other hand is in the Boron family with a total of 13 electrons.
The difference,( 34-13) electrons gives a total of 21 electrons
The element symbol in chemistry comprises atomic number and mass number.
Atomic number is written on the top of element and mass number is written at the bottom.
For eg:
If Y is an element that is having atomic number a and mass number x. Then its denotion will be:
ᵃYₓ.
So here ⁹F₁₈.₉₉
Here 18.99 will denote mass number while 9 will denote atomic number.
Answer is: Not all mixtures have solutes and solvents.
Solution is homogeneous mixture composed of two or more substances.
In aqueous solution, solvent is water and solute (for example salt) is a substance dissolved in water.
Homogeneous solution of salt and water can be separated with heating (evaporating the water).
Here's what I got. Hope it helps.
