The elements hydrogen and helium are exempted from the octet rule. The octet rule, as you might recall, states that elements prefer to have eight electrons in their valence shells. Hydrogen has a lone electron in its valence shell, and cannot begin to "borrow" electrons to create a shell with eight electrons in it. Remember that its electron, a 1s1 electron, is in the 1s shell. Helium has a full 1s shell with its two electrons (1s1, 1s2). It has no interest in any other electron configuration because its valence shell is full. The first two elements on the Periodic Table are the exceptions to the octet rule. A link can be found below.
Hydrogen and helium are formed in Sun.
Helium has more mass than hydrogen. Helium is composed of two protons and two neutrons, while hydrogen is a single proton.
nuclear fusion of hydrogen to form helium
Helium, hydrogen, and air are gases.
Hydrogen is the most common element in the universe as a whole; about 75% of the universe by mass is hydrogen (since hydrogen is also the lightest element, that means that the percentage by number of atoms is even higher) . Helium is second; oxygen is a fairly distant third.
The symbol for hydrogen is H, and the symbol for helium is He.
Hydrogen and helium
Hydrogen is H2. Helium is He.
Hydrogen and helium follow the duet rule, which means they strive to have a full valence shell with two electrons. Hydrogen can achieve this by gaining one electron, while helium already has a full valence shell with two electrons.
Hydrogen and helium are formed in Sun.
No. Helium and Hydrogen are two different elements.
No, helium is almost 4 times as heavy as hydrogen.
About 96% is hydrogen, about 3% helium.
helium
Helium is heavier than hydrogen. Hydrogen is the lightest and simplest element in the periodic table, while helium is the second lightest element.
Helium has more mass than hydrogen. Helium is composed of two protons and two neutrons, while hydrogen is a single proton.
Chemical symbol (not formula) of hydrogen is H and for helium is He.