Chapter 3 - Periodic Properties of Elements Flashcards
Who summarised the elements by periodic law effectively creating the modern day periodic table?
Dmitri Mendeleev
How are elements listed in periodic table?
by increasing atomic number
What are rows on the periodic table called?
periods
What do all elements in a period have?
same number of shells
What are columns on the periodic table called?
groups - have similar properties
What do the sides of the periodic table largely consist of?
left = metals, right = non-metals
What is electron configuration?
the use of the 4 quantum numbers to account for all electrons in an atom and designate which orbitals they occupy
What is the Pauli exclusion principle?
no 2 electrons in an atom can have the same 4 quantum numbers
What are orbitals in the same principal energy level in hydrogen?
degenerate (have the same energy)
In multi electron atoms what are subshells?
not degenerate (energy depends on l)
What is Coulomb’s law?
energy of charged particles depends on their charges and separation
What is shielding?
electron repulsion in lower orbitals that screen outer electrons from nucleus
effective nuclear charge Zeffective = Z (actual charge) - S (no. of electrons shielding)
What is penetration?
outer electron moves into region occupied by inner electrons
What is the Aufbau principle?
a guide for determining the filling order of orbitals
What are the 3 rules of the Aufbau principle?
lower-energy orbitals fill before higher energy orbitals
an orbital can only hold 2 electrons which must have opposite spins (Pauli exclusion principle)
If two or more degenerate orbitals are available follow Hund’s rule
What is Hund’s rule?
if 2 or more orbitals with the same energy are available, one electron goes into each until all are half full
What are core electrons?
electrons in lower-energy shells
What are valance electrons?
electrons in all the sublevels with the highest principle energy shell
What is the significance of valance electrons?
one of the most important factors in how an atom behaves both chemically and physically - periodic table is designed to quickly identify valance electrons
what are the s block elements?
groups 1 and 2