when atoms collide, what determines whether they will react by transfering electrons or by sharing electrons
When atoms collide, whether they react by transferring or sharing electrons is determined by the difference in electronegativity between the atoms involved.
Electronegativity is the measure of an atom's ability to attract electrons towards itself. If there is a large difference in electronegativity between two atoms, one of them will tend to attract electrons more strongly and act as an electron acceptor, while the other atom will act as an electron donor.
If the electronegativity difference is significant (usually more than 1.7 on the Pauling scale), the reaction will likely involve electron transfer. In this case, one atom will lose electrons to become a positively charged ion (cation) while the other atom gains electrons to become a negatively charged ion (anion). This ionic bond results from the electrostatic attraction between the oppositely charged ions.
On the other hand, if the electronegativity difference is small (usually less than 1.7), the atoms tend to share electrons. This sharing of electrons forms a covalent bond. In a covalent bond, electrons are shared between atoms to fill their respective electron orbitals and achieve a stable configuration.
To determine whether atoms will react by transferring or sharing electrons, you can look up the electronegativity values for the elements involved. The Pauling scale is commonly used to compare electronegativity, and many periodic tables indicate these values. If the electronegativity difference is large, the atoms are likely to react by transferring electrons, while a small difference suggests they will react by sharing electrons.