Answer:nonmetals
Explanation:
Elements with high electronegativities have a stronger tendency to attract electrons than elements with lower electronegativities.
We can use the idea gas law equation to find the number of moles of He in the balloon at STP
PV = nRT
where
P - standard pressure - 10⁵ Pa
V - volume - 3.8 x 10⁻³ m³
n - number of moles
R - universal gas constant - 8.314 Jmol⁻¹K⁻¹
T - standard temperature - 273 K
substituting these values in the equation
10⁵ Pa x 3.8 x 10⁻³ m³ = n x 8.314 Jmol⁻¹K⁻¹ x 273 K
n = 0.17 mol
number of He moles are 0.17 mol