On Earth it is relatively rare—5.2 ppm by volume in the atmosphere. Most terrestrial helium<span> present today is created by the natural radioactive decay of heavy radioactive elements (thorium and uranium, although there are other examples), as the alpha particles emitted by such decays consist of </span>helium<span>-4 nuclei.</span>
Answer: The empirical formula is 
Explanation:
If percentage are given then we are taking total mass is 100 grams.
So, the mass of each element is equal to the percentage given.
Mass of Br= 58.37 g
Mass of F = (100-58.37) = 41.63 g
Step 1 : convert given masses into moles.
Moles of Br=
Moles of F =
Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.
For Br = 
For F = 
The ratio of Br: F= 1 : 3
Hence the empirical formula is
Answer:
Cl⁻
Explanation:
Definition of atomic radii
The atomic radius is the distance between center of two bonded atoms.
Trend along period:
As we move from left to right across the periodic table the number of valance electrons in an atom increase.The atomic size tend to decrease in same period of periodic table because the electrons are added with in the same shell. When the electron are added, at the same time protons are also added in the nucleus. The positive charge is going to increase and this charge is greater in effect than the charge of electrons. This effect lead to the greater nuclear attraction. The electrons are pull towards the nucleus and valance shell get closer to the nucleus. As a result of this greater nuclear attraction atomic radius decreases.
Trend along group:
In group by addition of electron atomic radii increase from top to bottom due to increase in atomic number and addition of extra shell.
In this way Cl⁻ will have the largest atomic radii because one extra electron is added and its atomic number is already greater than fluorine.
Answer:
1, 2, 1
Explanation:
Please see the step-by-step solution in the picture attached below.
Hope this answer can help you. Have a nice day!
Answer:
A: as the liquid gets warmer more particles have sufficient energy to escape from the liquid. Eventually, particles in the middle of the liquid form bubbles of gas in the liquid.
A: the temperature will only increase once all the liquid particles change to gas.
Explanation:
