Chapter 5 The Periodic Table
Periodic Table Info
Periodic Table Development Dimitri Mendeleev (1834 – 1907) Arranged the elements by increasing ATOMIC MASS Produced the first PERIODIC TABLE – 1871 The table placed elements with similar properties in the same column Kept “holes” for undiscovered elements, and predicted the properties in advance
Mendeleev’s Periodic Table
Predicting Properties
New Periodic Table H. G. Moseley ( ) Rearranged the elements by ATOMIC NUMBER This is the MODERN PERIODIC TABLE
atomic number symbol name average atomic mass electron configuration What’s on the Periodic Table?
GROUP: vertical column (family) similar chemical properites PEROID: horizontal row same energy levels Reading the Periodic Table
Period Group
Periodic Table Groups
Metal Nonmetal Notes
Metal, Nonmetal, Metalloid
Properties of Metals 1.shiny (luster) 2.conductors of heat and electricity 3.reactive with acids 4.ductile –can be stretched into a wire 5. malleable –can be hammered or rolled into sheets 6. forms positive ions (by losing e - )
Properties of Nonmetals 1.dull and brittle 2.poor conductors of heat and electricity 3.does not react with acids 4.usually gases at room temp. 5.forms negative ions (by gaining e - )
Periodic Trends Notes
PERIODIC LAW When elements are arranged in order of increasing atomic number, their physical and chemical properties show a periodic (repeating) pattern. Which means: there are patterns across the periodic table called periodic trends
Atomic Radius half the distance from center-center of 2 like atoms
Atomic Radius DOWN a Group ↓As you go down a group: more energy levels larger atom size
Na Atomic Radius: down group P P P X P P P P P P P P P X X X X X X X X X X X
K P P P X X X P X P X P X P P P P P X X X X X P X X X X X X X X X
Atomic Radius DOWN a Group ↓DOWN THE GROUP ATOMIC RADIUS: INCREASES
Atomic Radius ACROSS a Period → Each atom gains 1 p + and 1 e - in the same energy level → Massive positive protons exert a greater force on the small electrons →energy levels are pulled closer to the nucleus
REMEMBER! PROTONS bigger and stronger! electrons smaller and weaker! P e
Atomic Radius: across period P P P X X X P X P X P X P P P P P X X X X X
Atomic Radius ACROSS a Period →ACROSS THE PERIOD ATOMIC RADIUS: DECREASES
amount of energy needed to remove an electron from an atom Ion: an atom that has gained or lost electrons if you lose an electron… if you gain an electron… Ionization Energy BECOMES POSITIVE! BECOMES NEGATIVE!
Ionization Energy DOWN a Group ↓Down a group atoms are larger, outer electrons are far from the nucleus and easily removed ↓Easier to remove Less energy needed
Ionization Energy DOWN a Group ↓DOWN THE GROUP IONIZATION ENERGY: DECREASES
Ionization Energy ACROSS a Period →Across a period, atoms get smaller →Across the period atoms want to gain electrons and NOT lose them →The more electrons present, the more energy required to remove them all to become STABLE
Ionization Energy ACROSS a Period →ACROSS THE PERIOD IONIZATION ENERGY: INCREASES
Watch the following animation: It is a “tug of war” between two atoms Electronegativity H F : : : Which is the more electronegative element?... Ability of an atom to attract electrons
Electronegativity DOWN the Group ↓Down the group, atom size increases ↓The larger the atom less likely it is to attract more electrons (lower ability)
Electronegativity DOWN the Group ↓DOWN THE GROUP ELECTRONEGATIVITY: DECREASES
Electronegativity ACROSS the Period →As you go across a period atoms get smaller because massive p + pull in the e - →Smaller the atom greater ability to attract electrons
Electronegativity ACROSS the Period →Metals do not attract electrons (lower ability to the left) →Non-metals do attract electrons (greater ability to the right)
Electronegativity ACROSS the Period →ACROSS THE PERIOD ELECTRONEGATIVITY: INCREASES
PUT IT ALL TOGETHER!
Reactivity Notes
Reactivity of Alkali Metals Reactivity of Metals Video 1 Reactivity of Metals Video 2
Where are the most reactive metals?
Where are the most reactive nonmetals?