A space-filling model shows the relative amount of space each atom takes up. In other words, a space-filling model can show relative sizes of atoms. However, unlike ball-and-stick or structural models, space-filling models do not show bond lengths clearly. Bonds are not really like sticks in a ball-and-stick model.
The rows are called Periods.
Answer:
The density of the ideal gas is directly proportional to its molar mass.
Explanation:
Density is a scalar quantity that is denoted by the symbol ρ (rho). It is defined as the ratio of the mass (m) of the given sample and the total volume (V) of the sample.
......equation (1)
According to the ideal gas law for ideal gas:
......equation (2)
Here, V is the volume of gas, P is the pressure of gas, T is the absolute temperature, R is Gas constant and n is the number of moles of gas
As we know,
The number of moles: 
where m is the given mass of gas and M is the molar mass of the gas
So equation (2) can be written as:

⇒ 
⇒
......equation (3)
Now from equation (1) and (3), we get
⇒ Density of an ideal gas:
⇒ <em>Density of an ideal gas: ρ ∝ molar mass of gas: M</em>
<u>Therefore, the density of the ideal gas is directly proportional to its molar mass. </u>
<span>I would say only if one of your data points is the origin. But your experiment could have started with a non-zero velocity, for instance, which would rule out the origin as one of your data points. Even so, a "best fit" is not meant to be perfect, it is only meant to be the best that you can do with your particular data set.</span>