Answer:
The answer is: D
Explanation:
A. They have the same number of electron energy shells. Is false, all the elements are in different periods so, they have different number of lectron energy shells.
B. They are all Halogens. No, is wrong, halogens are F, Cl ,Br
C. They have the same number of electrons. is wrong, if they had the same number of electrons they must be they same element and they aren't the same.
D. They are all Noble gases. Yes, it's true they are noble gases, they are the first group in the periodic table from the right.
Answer:
D
Explanation:
When lead ions and sulfate ions bond, they form sediment so neither a nor b can be the answer.
The important thing is that two nitrate ions were originally bonded with one lead ion, while two potassium ions bonded with a sulfate ion.
Finally, since potassium and nitrate ions don't form sediment these two ions must remain. Therefore the answer is D
Answer:
Avogadro number of representatives particles is equal to one mole.
Explanation:
The number 6.022 × 10²³ is called Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.
For example,
18 g of water = 1 mole = 6.022 × 10²³ molecules of water
17 g of ammonia = 1 mole = 6.022 × 10²³ molecules of ammonia
12 g of carbon = 1 mole = 6.022 × 10²³ atoms of carbon
1.008 g of hydrogen = 1 mole = 6.022 × 10²³ atoms of hydrogen
