2.2 Periodic Table Flashcards
Who’s the father of the periodic table?
Dmitri Mendeleev
Describe the first system of organizing the 62 known elements.
within rows and columns based on increasing mass and similar chemical and physical properties
Define Element
– substance that cannot ordinarily be broken down into similar substances
– not destroyed by acids
– not changed by electricity, light, heat
Elements have both __ and __ properties
– physical
– chemical
How does the arrangement of the modern Periodic Table differ as opposed to earlier?
arranged according to atomic #, not atomic mass
Name the three subdivisions of elements on the Periodic Table + their properties
- Representative elements: both metals and nonmetals
- Transition elements: metals
- Lanthanides and Actinides
Name the groups + locations within the Representative elements subdivision
– Group 1: Alkali Metals
– Group 2: Alkaline Earth Metals
– Group 17: Halogens
– Group 18: Noble Gases
What are rows on the periodic table called
periods
What are columns on the periodic table called
groups/families
the elements in each group have similar __ properties
physical/chemical
list some defining characteristics of Metals
– malleable
– ductile
– lustrous
– conductive
– positive electric charge
list some defining characteristics of nonmetals
– usually brittle
– dull
– non-conductive
– negative charges or neutral
Why does Hydrogen appear in both Group 1 and 17?
under certain circumstances can behave as if metallic or non-metallic
what is the atomic #
whole # equal to the # of protons in the element’s atom
define atomic mass
avg mass of an element’s atom compared to an atom of carbon-12
what are the diatomic molecules
H2, O2, F2, Br2, I2, N2, Cl2, At2
– HOFBrINCl
define Ionization Energy
energy required to remove an atom or molecule’s valence electron
define Atomic Radius
half of the distance b/w the centres of2 atoms of an element thru touch
define Electronegativity
measure of the attraction of an atom for the electrons in a chemical bond
Elements w/ high ionization energies have __ electronegativities becuz…
– high
– a strong pull exerted on electrons by the nucleus
Describe how the atomic radius, ionization energy, and electronegativity behave as u move left to right across the periodic table
– decreases
– increases
– increases
Describe how the atomic radius, ionization energy, and electronegativity behave as u move top to bottom in the periodic table
– increases
– decreases
– decreases
What is the most metallic group?
Alkali metals
Describe some chemical properties of Alkali Metals
– combining capacity: +1
– reactive
– react w/ oxygen to form oxides
Describe some chemical properties of Alkaline Earth Metals
– combining capacity: +2
– not as reactive as alkali metals
– react w/ oxygen to form oxides
– react w/ acids to release hydrogen gas
Describe some chemical properties of Halogens
– low melting/boiling points
– very reactive + poisonous
What is the strongest known oxidizing agent?
fluorine
List some chemical properties of Noble Gases
– very low melting/boiling points
– virtually non-reactive
– emit colours when they conduct an electric current
List some chemical properties of Transition elements
– metals
– hard + dense
– high melting/boiling points
– good conductors of heat + electricity
– vary greatly in chemical reactivity
– form many coloured compounds
– can have several different combining capacities
List some chemical properties of Lanthanides and where on the table they occupy
– atomic #s 57-71
– almost identical chemical characteristics
– very reactive
– react w/ water to produce hydrogen
– combining capacity of +3
List some chemical properties of Actinides and where on the table they occupy
– atomic #s 89-103
– radioactive
– most are synthetically prepared
– no elements preceding uranium occur in nature
– relatively short half-lives
