Ch. 6: The Periodic Table of Elements

Essential Questions What information does the Periodic Table provide about atoms? Why are the elements arranged in the way that they are? What are the trends of the elements of the PTE?

Mendeleev’s PTE

The genius of Mendeleev’s periodic table Lou Serico

Henry Moseley In 1913, Henry Moseley discovered atomic numbers Previously, elements were organized mostly by their masses (though Mendeleev went mostly by mass, he adjusted here and there to fit properties)

Periodic Law Elements are arranged in order of increasing atomic number. There is a periodic repetition of physical and chemical properties.

Periods and Groups

Blocks of Elements

Metals, Non-Metals & Metalloids

Metals, Non-Metals & Metalloids Properties Metals – generally good conductors of heat and electricity Non metals are poor conductors Metalloids are somewhere in between (sometimes they behave like a metal, sometimes they behave like a nonmetal)

Metals, Non-Metals & Metalloids Properties Metals – have high melting and boiling points Non metals – have low melting and boiling points Metalloids – low melting points, high boiling points

Melting and Boiling Point Temperature in Celsius where there is a phase change from solid to liquid and then from liquid to gas.

Organizing by Groups What is the electron configuration for Li? What about Na? K? Rb? Notice something?

Groups of the PTE

Solving the puzzle of the periodic table Eric Rosado

Properties of Elements Reactivity Atomic Radius Melting and Boiling Point Ionization Energy Electronegativity Density

Reactivity Metals get more reactive down a group Non metals get less reactive down a group

Reactivity You Try What is the most reactive Halogen? What is the least reactive Alkali metal?

Atomic Radius The radius of one atom of an element.

Atomic Radius You Try What is the largest Noble Gas? What is the smallest Alkaline Earth Metal? Rank by atomic size: Ba, Ca, Zn, Se, O

Ionization Energy The energy (quanta) needed to remove an electron from a neutral atom. Neutral-same number of protons and electrons.

Why?

Ionization Energy You Try What Halogen has the largest Ionization energy? What Noble gas has the smallest Ionization energy? What Period 2 element has the smallest ionization energy?

Electronegativity The ability of an atom to attract electrons when the atom is in a compound. Important for bonding with other atoms.

Electronegativity You Try What alkali metal has the largest electronegativity? What transition metal most likely has the lowest electronegativity? Rank from largest to smallest electronegativity: Ga, O, P, Ge, N, Si, F

Periodic Trends Activity You will research the properties of different elements. You will organize them in excel, graph them, insert the graphs into a word document, and complete the questions about the trends of each property.