Periodic Table Notes Feb 16 Write everything in black font

Atoms-are the smallest building blocks of matter, they cannot be created, destroyed or divided. Exception: Atoms can be split by nuclear reactions and created in labs

Structure of Atoms In neutral atoms the # of protons in the nucleus equals the # of electrons, but the neutrons can be different If the atom is charged (lost/gained some e-), it is called an ION (Example Na+ ions) p p p p p p Protons (p+) Neutrons (n 0 ) Nucleus Electrons (e-) Shell 5 5 4

Different Elements have atoms with their own unique number of protons and electrons Oxygen has 8 protons How many electrons? 8 electrons Oxygen also has 8 neutrons p p p p p p p p One element might have some atoms with more neutrons than others – ISOTOPES Some carbon atoms have 8 neutrons, some have 6 neutrons – Carbon-14 and Carbon-12 are used for carbon dating

Atoms combine to make compounds and molecules Water – H 2 O 1 Oxygen 2 Hydrogens Sugar – C 6 H 12 O 6 Nitrogen in the air – N 2

History of the Table -Back in the 1800s, scientists started to notice patterns in the properties of the elements. -Mendeleev then was able to predict the properties of elements that had not yet been discovered. -In 1860, Dmitri Mendeleev organized the known elements based on these patterns to make the first periodic table.

The Periodic Table: A way of arranging the elements based on patterns that are seen in their properties. When elements have similar properties, they are placed in the same column on the table.

Groups: The columns on the periodic table. Elements in the same group have similar properties. Example: Group 1 elements all react violently with water. Group 18 elements do not react with anything and are gases

Periods: Rows on the periodic table. Elements in the same row have very different properties. They are lined up by atomic number in the rows. Example: Xenon which is a gas that doesn’t react with anything is in the same period as Rubidium which will cause an explosion in water.

How to read the Periodic Table B Boron Atomic Symbol Element Name Atomic Mass Atomic Number

What do the numbers mean? B Boron Atomic number: how many protons are in the nucleus and how many electrons the element has. Atomic mass: how much the atom weighs and 5 protons 5 electrons 6 neutrons Mass - atomic# = #of neutrons

Abbreviations – it’s a matter of life and death: One capital letter or a capital and a lower case – you MUST follow this rule CO is a compound called carbon monoxide that kills you Co is an element called cobalt that is part of essential vitamins

Practice Problems: For each of these elements, identify how many p+, e- and n 0 it has and name one other element that has similar properties 1.Sodium 2.Calcium 3.Carbon 4.Neon 11p+, 11e-, 12n 0, Potassium/Lithium/etc.