Chemical Bonding Flashcards
what is an ion
a charged atom or group of atoms
what happens when an atoms loses one or more electrons
it becomes a positive ion called a cation
why do elements in group 1 form ions with a charge of +1
because they lose one electron to have a stable electron arrangement
what happens when an atom gains one or more electrons
they become a negative ion called a anion
why does the gain of an electron from an atom always produce a negative ion
there are more negative charges than positive so the atom becomes a negative ion
what is an ionic bond
the electrostatic force of attraction between the positive and the negative ions as a result of electron transfer
what is an ionic bond formed between
a metal and a non-metal
what is the structure of ionic compounds
a giant ionic lattice
how are ions held together in ionic compounds such as NaCl
the strong electrostatic attractions between the positive and negative ions hold the ions together in sold NaCl
what are the properties of ionic compounds
they have high melting/boiling points
conduct electricity when melted or dissolved in water
mostly all ionic compounds are soluble in water
solids at room temperature
why do ionic compounds have high melting/boiling points
they have a giant ionic lattice with strong electrostatic forces of attractions between the positive and negative ions. A large amount of energy is needed to break the strong ionic bonds and make the ions mobile
why do ionic compounds only conduct electricity when molten or dissolved in water
when they are melted or dissolved in water, the ions can move and carry the charge but when the compounds are solid the ions can’t move and just vibrate around their fixed positions
what is a covalent bond
a pair of electrons shared between two atoms
what is a covalent bond formed between
two non-metals
what is the structure of covalent compounds
a simple molecular strucutre
why do larger molecules have higher boiling points than smaller molecules
larger molecules have more intermolecular forces
what are the properties of covalent compounds
they have low boiling points
they don’t conduct electricity
often insoluble in water but soluble in organic solvents
why do covalent compounds have low boiling points
they have a simple molecular structure. They are made up of small molecules with weak forces between the molecules and little energy is needed to break these weak intermolecular forces
why do covalent compounds not conduct electricity
there are no free electrons as the outer electrons are all fixed in covalent bonds