Explanation:
Valence electrons is the number of electrons in the outermost shell of an atom. For the main group elements, the group number represents the number of valence electrons.
Beryllium
This belongs to the group 2 hence, it has valency of 2.
Nitrogen
This belongs to group 5, hence it has valency of 5.
Oxygen
This belongs to group 6, hence it has valency of 6.
Fluorine
This belongs to group 7, hence it has valency of 7.
Magnesium
This belongs to group 2, hence it has valency of 2.
Phosphorus
This belongs to group 5, hence it has valency of 5
Sulphur
This belongs to group 6, it has valency of 6
Chlorine
This belongs to group 7, it has valency of 7
A model represents a place thing or idea. A made is a model as it shows a place and represents the place it’s showing such as a globe
Answer:
In the case of liquids and solids, the distances between particles are negligible,
Explanation:
On temperature 25°C (298,15K) and pressure of 1 atm each gas has same amount of substance:
n(gas) = p·V ÷ R·T = 1 atm · 20L ÷ <span>0,082 L</span>·<span>atm/K</span>·<span>mol </span>· 298,15 K
n(gas) = 0,82 mol.
1) m(He) = 0,82 mol · 4 g/mol = 3,28 g.
d(He) = 10 g + 3,28 g ÷ 20 L = 0,664 g/L.
2) m(Ne) = 0,82 mol · 20,17 g/mol = 16,53 g.
d(Ne) = 26,53 g ÷ 20 L = 1,27 g/L.
3) m(CO) = 0,82 mol ·28 g/mol = 22,96 g.
d(CO) = 32,96 g ÷ 20L = 1,648 g/L.
4) m(NO) = 0,82 mol ·30 g/mol = 24,6 g.
d(NO) = 34,6 g ÷ 20 L = 1,73 g/L.
The correct answer would be... Scientific
