How do atoms or molecules know what other atoms or molecules to form bonds with?

the electrical charge or the lone pair of electrons which are unstable.l

Its the magnetic charges in the atoms depending on the number of positive charges (protons) and negative charges (electrons) for example H2O is water The 2H(hydrogen) has a Negative charge and the 1 oxgen has a large poitive charge so when 1 Oxgen atom gets one hydrogen atom it make a less positive charge and when the 2nd one comes and makes H2O it gains enough negative charge to cancel out the big positive one from the Oxygen and that is why water doesn bond with anything because its neutral. that is why we have to use elctricity to break down water instead of a chemical reaction.

How do atoms or molecules know what other atoms or molecules to form bonds with? Do they repel each other if they are not supposed to bond with each other? What causes repulsion between atoms or molecules? Each atom has protons and neutrons in the nucleus and electrons in the space outside the nucleus. The number of protons equals the number of electrons, so you might think that all atoms are stable. However, the stability of an atom depends on the number and arrangement of the electrons in the shells and the distance between the positive charged nucleus and the outer shell electrons. The most stable arrangement of outer shell electron is 2 electrons in the s orbital and 6 in the p orbital. This makes 4 pairs of electrons, which is commonly called an octet. The next most stable arrangement is 1 electron in the s orbital and 1 electron in each of the 3 p orbitals. In atoms with more shells, the distance between the nucleus and the outer shell electrons is greater. So, the force of attraction between the positive charged protons in the nucleus and the negative charged electrons is less. All this information is included in the electronegativity of the atom. Look at an electro-negativity table at the web site below http://en.wikipedia.org/wiki/Electronegativity Atoms of elements with high electronegativity have a stronger attraction for electrons. The nonmetals, in columns 16 and 17, have a much higher electronegativity than the metals in columns 1 and 2. When an atom of high electronegativity collides with an atom of low electronegativity, the atom of high electronegativity will attract 1 or more electrons from the atom of low electronegativity. Example: Na has 1 electron in the 3s orbital Cl has 2 electrons in the 3s and 5 electrons in the 3p Na = 0.93, Cl = 3.16 % Ionic character = 100 * (3.16 – 0.93) ÷ 3.16 = 70.6% During the collision of 2 Na atoms and 1 Cl2 molecule, each of the 2 Cl atoms attracts 1 electron each from each Na atom. The result is 2 Na+1 ions and 2 Cl-1 ions, which form an ionic bond. Table salt, NaCl, is forms a crystalline solid composed of these + and – ions. 2 Na + Cl2 → 2 Na+1 + 2 Cl-1 Now the Na+1 ion has 2 electrons in the 2s and 6 electrons in the 2p. and Now Cl-1+1 ion has 2 electrons in the 3s and 6 electrons in the 3p. Both ions are very stable, because the s and p orbitals of the outer shell contains 4 pairs of electrons, which is the most stable arrangement. H has 1 electron in the 1s orbital O has 2 electrons in the 3s and 4 electrons in the 3p H = 2.20, O = 3.44 % Ionic character = 100 * (3.44 – 2.20) ÷ 3.16 = 36% During the collision of 2 H2 molecules and 1 O2 molecule, each O atom attracts 2 electrons from 1 H2 molecule, forming 2 H2O molecules 2 H2 + O2 → 2 H2O Because the % Ionic character is less, the force of attraction is less. So the bond between the O atom and H atom is polar covalent bond. The pair of electrons which forms the bond is attracted toward the O atom. This make the O end of an H2O molecule have a partial negative charge. And the end with 2 H atoms has a partial positive charge. So water molecules are attracted to each other when the O end of 1 H2O molecule collides with the H’s end of another H2O molecule. If the % Ionic character is close to 0, the bond electrons are shared by 2 atoms. So the molecule is nonpolar, which means no atom has a partial – or + charge. Diatomic molecules, such as H2, N2, O2, and the halogens in column 17, have very little attraction for each other. They exist as liquids, only when the temperature is extremely low. The atoms of metals are bonded together by sharing valance electrons in a “sea of free electrons”, which holds the entire piece of metal together. In the molecules of nonmetals, such as carbon and sulfur, the atoms exist in a structure composed of covalent bonds. Do a web search for various atoms and molecules and you will the various structures. Do they repel each other if they are not supposed to bond with each other? YES When 2 water molecules collide with the positive or negative ends facing each other, one of the molecules will rotate, so the opposite ends can attract each other. What causes repulsion between atoms or molecules? Atoms or molecules will only repel each other if 2 positive or 2 negative parts of a molecule approach each other. Always remember that atoms and molecules are always vibrating and / or moving, because the temperature is always above absolute zero!! As atoms and molecules in their most stable equilibrium structure are always attracting and repelling as they come too close and move too from each other.

Its the magnetic charges in the atoms depending on the number of positive charges (protons) and negative charges (electrons) for example H2O is water The 2H(hydrogen) has a Negative charge and the 1 oxgen has a large poitive charge so when 1 Oxgen atom gets one hydrogen atom it make a less positive charge and when the 2nd one comes and makes H2O it gains enough negative charge to cancel out the big positive one from the Oxygen and that is why water doesn bond with anything because its neutral. that is why we have to use elctricity to break down water instead of a chemical reaction.

the electrical charge or the lone pair of electrons which are unstable.l