How do you get H2O.....?

Question

2 is a subscript, I know because Hydrogen has 2 atoms and Oxygen has 1 atom. How do you know how many atoms it has? and how do you get the number 2!!!!? Does the period (You know Hydorgen is period 1) has a role to play in it.

Answer 1

You are needlessly confusing yourself.

H2O

H2 and O. Two atoms of Hydrogen and one atom of Oxygen. The numbers come straight from the chemical formula.

H2 (2 atoms)
O (1 atom)

This has nothing to do with periods.

Answer 2

Let's begin with an atom of hydrogen. It has a nucleus...the center of the atom and a ring (let's call it a satellite ring) and in this ring is our little satellite...but it is not happy...it's lonely and would like a friend....well our little lonely friend can find another hydrogen atom and then the two satellites (electrons) can be friends and they are satisfied. Stay with me! I am being very simple but the chemistry is exact...now our little guys have satisfied the electron ring for both....they share electrons and have become a molecule....some atoms are complete and do not need additional electrons...for example helium has two electrons and so it is satisfied and therefore such inactive atoms/molecules are called inert (Not Active) and do not react with other chemicals. Oxygen has two rings, the inner ring has two electrons but the outer ring has only 6 electrons ( K ring is happy with 2 electrons but the L ring needs 8 to be stable)....Atomic Numbers help you to understand how many electrons/protons an element has...Hydrogen is 1 (so it needs to gain one electron to be satisfied....oxygen is number 8....so two electrons in the K ring and only 6 in the outer ring so it needs two)
So two hydrogen atoms join with one oxygen atom...so the hydrogen atoms share their electrons with the oxygen and the oxygen atom shares its electrons with the two hydrogen guys and there is a big party because everyone is happy. Water is stable because it is satisfied by electrical bonding. We can use many terms but understanding the concept is critical to make chemistry fun and easy. The periodic table is very useful...remember that the vertical columns are groups and the horizontal rows are called periods. Chemicals within a group share similar properties...those in a period show no direct relationship, only increasing atomic weight...So lithium with the atomic number 3 is just below hydrogen in the periodic table and also like hydrogen needs electrons to complete its outer ring is a very reactive metal and often bond with oxygen.

Answer 3

Hydrogen's outer shell (the K shell) can hold two electrons. It has only one so it's outer (only) shell has one empty space. Oxygen's outer shell (the L shell) can hold eight electrons. It has six so it has two empty spaces. The atoms of Hydrogen and Oxygen covalently bond. An electron from each of two hydrogen atoms fills the two empty spaces in the single oxygen atom while an two electrons from oxygen fill the empty spaces in the shells of the hyrogen atom. Think of the atoms as jigsaw puzzle pieces. The hydrogen pieces have one bulge or extension (their one electron) and the oxygen pieces have two depressions or indentations (their two empty spaces). The pieces will fit together only one way - two hydrogens and one oxygen. H20.

Answer 4

The group, not the period, has a role to play in the reason. The group basically means the number of electron each atom of the element has in its outermost orbital.

Oxygen is in group 6. This means it has 6 electrons in its outermost orbital. The most electrons an element can have in its outermost shell, with just two orbitals as oxygen has, is 8. This means that oxygen has two free spaces in its outermost orbital.

Hydrogen is in group 1. This means it has 1 electron in its orbital. The most electrons the first orbital can have is 2. This means that hydrogen has one free space in its orbital.

All elements "like" to have full orbitals, meaning the maximum number of electrons per orbital.

When an atom of oxygen comes together with two atoms of hydrogen, they share electrons, so that every orbital from both elements is full. The oxygen gains two electrons, one from each hydrogen, and the hydrogens each gain one electron, from the oxygen. That is why there are two hydrogens, and one oxygen- The oxygen needs two electrons, but has enough to share with the hydrogens as well.

Answer 5

Water is a molecule with three atoms- 2 of hydrogen and one of oxygen. Hydrogen is stable in nature as H2. Oxygen also is stable as O2. But when hydrogen burns you get (2)H2 + (2)O2= (2)H2O + O2.





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Answer 6

Water has 3 atoms.

Answer 7

There are 2 hydroden atoms as they each have a charge of +1, while oxygen has a charge of -2, likewise due to polarity, opposites attract and they bond together to become stable...