2 valence electrons
Explanation:
Most transition metals have 2 valence electrons. Valence electrons are the sum total of all the electrons in the highest energy level (principal quantum number n). Most transition metals have an electron configuration that is ns2(n−1)d , so those ns2 electrons are the valence electrons.
Answer:
Decreases
Explanation:
The particles have more space to move and will be less likely to collide.
Answer:
The volume of the vessel is 250 L
Partial pressure of hydrogen = 189 torr
Explanation:
Using Boyle's law

Given ,
V₁ = 20.0 L
V₂ = ?
P₁ = 25 atm
P₂ = 2 atm
Using above equation as:




<u>The volume of the vessel is 250 L.</u>
According to Dalton's law of partial pressure:-

So, according to definition of mole fraction:

Also,
Mole fraction of H₂ = 1 - Mole fraction of He = 1 - 0.75 = 0.25
So,
Total pressure = 756 torr
Thus,

<u>Partial pressure of hydrogen = 189 torr.</u>