Why is helium used to fill balloons instead of oxygen?

Helium is placed at the top, or in the first position, of a periodic table. It as an atomic number of 1. read more

Because helium is lighter than air (the air is mixture of nitrogen, oxygen and some other gases) so the balloons fly, while oxygen is (slightly) heavier than air and the balloons will just fall to the ground. read more

Helium is used to fill balloons instead of oxygen or hydrogen is because helium is lighter than air while oxygen and hydrogen are denser so they do not make the balloon float in the air because of gravity. read more

Helium is used in balloons instead hydrogen as it is a highly combustible gas and if the balloon brusts it may cause damage to our skin or cause burns in our hands . Hence helium is a convenient for filling in balloons. read more