Usually (ignoring transition metals, as they kinda get trickier), the element's valency can be found out by its group (column) number. Usually, we ignore the transition metal block while counting these columns, so Aluminium is in group 3, for example. Since Aluminium is in group 3, it has 3 valence electrons.
Answer:
(a) 0.25 mol
(b) 0.11 mol
(c) 8.77 mol
Explanation:
(a)
We use the equation given by ideal gas which follows:
where,
P = pressure of the gas = 1.00 atm
V = Volume of the gas = 6.0 L
T = Temperature of the gas = 298 K
R = Gas constant =
n = number of moles = ?
Putting values in above equation, we get:

(b)
We use the equation given by ideal gas which follows:
where,
P = pressure of the gas = 0.296 atm
V = Volume of the gas = 6.0 L
T = Temperature of the gas = 200 K
R = Gas constant =
n = number of moles = ?
Putting values in above equation, we get:

(c)
We use the equation given by ideal gas which follows:
where,
P = pressure of the gas = 30 atm
V = Volume of the gas = 6.0 L
T = Temperature of the gas = 250 K
R = Gas constant =
n = number of moles = ?
Putting values in above equation, we get:

Answer: An atom that has gained an electron.
Explanation:
The number of protons in an atom cannot change except for some exceptional circumstances.
Cations (or metal ions) are formed when atoms lose electrons, as they want to form a complete outer electron shell to become as stable as possible.
For example, potassium is a 1+ ion, because it has one electron in its outer shell (and in group one). Therefore, to become more stable that electron is lost to become an ion or cation. As one electron is lost, the potassium cation charge is 1+ as the charge of an electron is 1-.
Answer: You can probably go onto <em><u>You Tube and find that answer!</u></em> Just be <u><em>detailed in your search!</em></u> Hope this helps!
Explanation:
Just Simple Physics :P