Introduction to the Periodic Table Atomic Number Symbol
Introduction to the Periodic Table Atomic Number ● Symbol ● Atomic Weight Element ● Compound ● Mixture
Element, Compound Molecule or Mixture?
Element, Compound Molecule or Mixture?
Element, Compound Molecule or Mixture?
Element, Compound Molecule or Mixture?
Element, Compound Molecule or Mixture?
Element, Compound Molecule or Mixture?
The Periodic Table
Why is the Periodic Table important to me? The periodic table is the most useful tool to a chemist. u You get to use it on every test. u It organizes lots of information about all the known elements. u
Pre-Periodic Table Chemistry … …was a mess!!! u No organization of elements. u Imagine going to a grocery store with no organization!! u Difficult to find information. u Chemistry didn’t make sense. u
Pre Periodic Table History u u The earliest attempt to classify the elements was in 1789, when Antoine Lavoisier grouped elements based on their properties into gases, non-metals, metals and earths. Several other attempts were made to group elements together over the coming decades. (ex: Newlands, Beguyer de Chancourtois, Dalton)
John Dalton (1808)- Atomic Theory u u Dalton proposed a theory to explain “atoms” up to the 1800’s Built off of Democritus’ idea of the uncuttable “atomos” 1. Elements consist of tiny, indivisible particles called atoms, which for a given element are identical in size, form and mass 2. Different elements have different sizes forms and masses 3. Atoms are unchangeable atoms of one element never change into atoms of another element 4. Compounds are unions of 2 or more elements. 5. The unit containing the smallest number of atoms whose union constitutes a compound is called a molecule 6. Atoms combine in simple whole number ratios
I am Dmitri Mendeleev! (1860) I made the PERIODIC TABLE !
Dmitri Mendeleev: Father of the Table HOW HIS WORKED… u Put elements in rows by increasing atomic weight. u Put elements in columns by the way they reacted. u u SOME PROBLEMS… He left blank spaces for what he said were undiscovered elements. (Turned out he was right!) He broke the pattern of increasing atomic weight to keep similar reacting elements together.
Periodic Table Cards u Fill in the missing parts of the sequence… 1. 2. 3. 4. Monday, Tuesday, Wednesday, _______, _______ One, two, four, eight, ______, _______ January, _______, March, ______, May, ______ O, T, T, F, F, ___, ____, ____ What did you need to consider to complete the sequence?
Card Array • • • Examine the cards provided. Not all cards are present. You will have empty spaces in your array Sketch, to the best of your ability what you believe the missing cards to look like Make your sketch on the blank sticky notes Arrange your cards on your desk in an array (see side picture) and have Mrs. Carter check your answer
Reflection Questions u On your sheet answer the following: 1. How did you infer, from the cards around the empty spaces, what to draw in your spaces? 2. What could help you create a better more accurate drawing for the empty spaces? 3. Based on the class discussion, how was the process similar to what Dmitri Mendeleev accomplished with the periodic table?
The Current Periodic Table. Henry Moseley u Mendeleev wasn’t too far off. u Henry Moseley (1913): Now the elements are put in rows by increasing ATOMIC NUMBER!! Instead of atomic mass (like Mendeleev) u The horizontal rows are called periods and are labeled from 1 to 7. u The vertical columns are called groups are labeled from 1 to 18.
What is the PERIODIC TABLE? o Shows all known elements in the universe. o Organizes the elements by chemical properties.
How do you PERIODIC read the TABLE?
What is the ATOMIC NUMBER? o o The number of protons found in the nucleus of an atom Or The number of electrons surrounding the nucleus of a NEUTRAL atom.
What is the SYMBOL? o o An abbreviation of the element name. Standard across all languages Used to write chemical formulae First letter is always CAPITAL and second letter is ALWAYS lowercase
What is the ATOMIC WEIGHT? o o o The number of protons and neutrons in the nucleus of an atom. Calculated as an average from the ISOTOPES of an element Isotope: same element; different number of _______ in the nucleus (eg: Carbon-13)
How do I find the number of protons, electrons, and neutrons in an element using the periodic table? o # of PROTONS = ATOMIC NUMBER o # of ELECTRONS = ATOMIC NUMBER (for NEUTRAL ATOMS) o # of NEUTRONS = ATOMIC _ ATOMIC WEIGHT NUMBER
Entry Slip u On a sheet of looseleaf answer the following: 1. How are the elements arranged on the modern periodic table? 2. What information can you find from the element squares on the periodic table? 3. What was something you thought was confusing or need more help with?
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