periodic trends Flashcards
atomic number
determines the placement and order of an atom
electronegativity
indicates an atoms ability to attract electrons in a chemical bond , increases from left to right across a period and decreases and you move down a group
atomic size
periodic trend that is influenced by electronic configuration
atomic radius
the distance between the nuclei and the outer most electron , increase as you move down a group and decrease from left to right in a period
ionic radius
the distance between the nuclei of an ion and the outer most electron, increases as you move down a group and decreases from left to right in a period
ion
an atom or a bonded group of atoms with a positive or negative charge , when atoms form ions they become charged and their radius changes
why do atoms become smaller when they become positively charged , 2 answers
the loss of valence electrons can leave an empty outer shell
electrostatic repulsion decreases allowing the electrons to get pulled by the nuclei
why do atoms become bigger when they become negatively charged
the addition of electrons increases electrostatic repulsion
ionic radii of positive ions and negative
for positive :decreases from left to right with in a period
for negative : decrease from left to right from group 15 of 16
for both: increases in size as you move down a group
ionization energy
the energy required to remove an electron from a gaseous atom increases from left to right in a period and decreases down a group
first ionization energy
the energy required to remove the first electron , removing the second on is called second ionization energy and so on. each level of ionization requires more energy but it is not a steady increase
why does the ionization trend increase and decrease the way it does
as atomic size increase less energy is required to remove an electron hence the electron is further away from the nuclei
octet rule
states that atoms tend to gain lose or share electrons in order to obtain eight valence electrons to be stable
