Periodic Table Flashcards
modern periodic law
physical and chemical properties of elements are periodic functions of their atomic numbers
modern periodic table correlates position of element with
electronic configuration
define bridge elements
show similarities in properties diagonally with the period of the next group
what happens to electronegative character across period
increases
what happens to electropositive character across period
decreases
metasilisic acid formula
H2SiO3, weak acid
perchloric acid formula
HClO4, strong acid
chlorine heptoxide formula
Cl2O7, strongly acidic
phosphine formula
PH3, weaker base
metaphosphoric acid formula
HPO3, weak acid
orthophosphoric acid
H3PO4, weak acid
transition elements have how many valence electrons
2
metallic character down a group
increases
periodicity in properties of elements mean
occurrence of characteristic properties of elements at regular intervals in the modern periodic table, when elements are arranged in increasing order of their atomic numbers.
define ionisation potential
the amount of energy required to remove an electron from the outermost shell of an isolated, gaseous atom.
define electron affinity
the amount of energy released when an atom in the gaseous state accepts an electron to form an anion
define electronegativity
tendency of an atom to attract electrons to itself when combined in a compound
what happens to atomic radius when nuclear charge increases
atomic size decreases, because electrons of outermost shell are attracted with more force.
define nuclear charge
positive charge on the nucleus of an atom. it is equal to its atomic number
atomic radius across the period
decreases
why do noble gases have larger atomic radius in a period
the outermost shell is filled, so there is repulsion. nuclear pull over valence electrons is not seen, so radius is maximum
atomic radius down a group
increases (nuclear charge increase down a group, but increase in number of shell dominates increase in nuclear charge)
what happens to IP when radius increases
decreases (nuclear attraction on outermost shell decreases, so less energy needed)
what happens to IP when nuclear charge increases
increases
why do metals have lower IP than non metals
because they lose electrons
IP across a period
increasesI
IP down a group
decreases
what happens to EA when radius increases
decreases, because smaller the atom, the more readily it takes up electrons, so more energy released.
which elements have highest EA
halogens
which elements have 0 EA
noble gases
greater the value of EA…
more electronegative/ more oxidising is the element
EA across a period
increases
EA down a group
decreases
electronegativity (EN) indicates what?
net result of the tendency of elements to attract the bond forming electron pair
most EN element
fluorine
least EN element
caesium
EN across a period
increases
EN down a group
decreases
what happens to metallic and non metallic character when ionisation potential decreases
increases, decreases
metallic character across period
decreases
non metallic character across period
increases
most metallic elements
at bottom of the group, because they have largest AR, lowest IP
metallic character down a group
increases
non metallic character down a group
decreases
density across a period
increase gradually (slight decrease thereafter)
density down a group
increases (so m.p and b.p decrease)
define light metals
elements arranged in periodic table having n/p ratio around 1 (stable elements)
define heavy metals
elements having n/p ratio more than 1.5 (unstable elements)
