chapter 4 - ionic compounds Flashcards
what is electronegativity and what group of elements have high electronegativity - what does this mean in terms of ionic compounds
electronegativity = ability to attract electrons non-metals = high electronegativity so they take electrons from metals to form ionic compounds
in what way can the formation of ions or ionic bonds be shown
electron transfer diagram
what is special about beryllium
even though it is a metal it has high electronegativity so instead of forming ionic compounds, it mainly forms covalent bonds instead (shares electrons with another atom)
list teh properties of ionic compounds
- solid at room temp
- hard but brittle
- high melting point and boiling point
- cant conduct electricity unless molten or dissolved in water
what substances does ionic compounds dissolve in
some dissolve in water and other polar substances. none dissolve in non-polar substances
define a non-polar sunstance
non-polar molecules has no net dipole moment meaning that there is no difference in electronegativity between the atoms in the compound (either in an ionic or covalent molecule)
how is electricity conducted by dissolved/molten ionic compounds
since they are liquid the ions are broken apart and are able to move freely. when a negative and positive electrode are placed in the water the anions move towards the positive electrode and the cations move towards the negative electrode creating a electric current
what is an important aspect when deciding the formula for an ionic compound
it cant have a net charge to the negative and positive charges must balance out
what are some characteristics of polyatomic ions
- contain 2+ ions
- behave as a single unit with a charge
- found in a fixed ratio
what is electrovalency and how does it differ in transition metals
electrovalency is the charge on an ion. transition metals can have several electrovalencies which are shown by roman numerals in brackets after the ion.
define a polyatomic ion
2+ atoms in a fixed ratio with a singular charge
