Explain why the first ionisation energy of helium is
larger than that of hydrogen.

Answer

Explanation:

helium has a structure 1s² the electrons are removed from the same orbital as in case of hydrogen the electrons are closest to the nucleus the value of ionization energy of helium is much higher than hydrogen  because the nucleus now has 2 proton attracting  the electrons instead of 1 in case of hydrogen

Mass is the amount of matter in an object.  weight is the measurement of the pull of gravity on an object.  say for example, you travel to the moon which has a different gravitational field compared to the gravitational field of earth. (gravitational fields: earth = 1, moon = 0.165)  now when you are on the moon, the pull of gravity on you is different than on the earth. and as weight is the measurement of the pull of gravity on an object, that means yes, your weight can and will change on the moon.  however, on the moon, on earth or even on jupiter, the amount of mass inside of you remains the same. meaning your physical mass remains constant.  in conclusion it is possible for your weight to change as your mass remains constant. 

Ibelieve the answer is weathering,hope my answer has you : )