Chapter 3 Elements The Periodic Table 3 2

Chapter 3: Elements & The Periodic Table 3 -2: ORGANIZING THE ELEMENTS

Why is Mendeelev’s periodic table the one that has endured? genuis-of-mendeleev 1. Who is credited with creating the periodic table? a) Isaac Newton b) Dmitri Mendeleev c) Albert Einstein d) Cecil George Paine

Why is Mendeelev’s periodic table the one that has endured? genuis-of-mendeleev 2. What did Dmitri Mendeleev do that set him apart? a) Created a list of all the known elements b) Arranged all the known elements together based on their properties c) Made accurate predictions about undiscovered elements based on where they would be located on the periodic table d) Accidentally discovered Plutonium

Why is Mendeelev’s periodic table the one that has endured? genuis-of-mendeleev 3. What is the English translation for Sanskrit world ’eka’? a) element b) Periodic c) Aluminum d) one

Why is Mendeelev’s periodic table the one that has endured? genuis-of-mendeleev 4. How many scientists have an element named after them? a) 5 b) 6 c) 15 d) 35

Dmitri Mendeleev v. Noticed some elements behaved the same v. Wondered if they could be organized by any specific pattern v. Focused on melting point, density, color, atomic mass v. Published first periodic table of 63 elements in 1869

Modern Periodic Table v. Shows all the different atoms (elements) on Earth. v. Rearranged according to atomic number in 1913 v. More consistent pattern v. Currently 118 elements

How do we find an element? Periods ◦ Horizontal rows going left and right ◦ Period numbers are down the left side Groups ◦ Vertical columns going down ◦ Group numbers are across the top of the periodic table Use them like battleship

v. The element in period 5 group 17 is: I (iodine) Ca (calcium) v. The element in period 4 group 2 is: 1 1 2 13 14 15 16 17 2 3 4 5 6 7 8 9 10 11 12 18

How do we read an element’s square? v. Always the same information v. Read from top to bottom v. Tells you 7 things Atomic symbol Atomic name Atomic mass = # protons + # neutrons

Example 79 ◦ Atomic number = _______ 79 ◦ # protons = ______ ◦ # electron = ______ 79 ◦ Atomic symbol = ______ Au ◦ Atomic name = ______ Gold 197 ◦ Atomic mass = ______ ◦ # Neutrons = ______ 118 197 – 79 = 118

v. Left to right, atomic number: increases v. Left to right, atomic mass: increases 1 v. Down a group: 1 18 18 2 13 14 15 16 17 2 3 4 5 6 7 8 9 10 11 12

v. Left to right, atomic size: decreases v. Down a group, atomic size: increases

What can we tell about this element from the Periodic Table? 1. The element’s (atom’s) name. Nitrogen 2. The symbol for nitrogen. (N) 3. The number of protons (7) ◦ From the atomic number 4. The atomic mass (14. 007) ◦ (protons + neutrons = atomic mass) 5. How can we determine the number of neutrons in nitrogen? ◦ Atomic mass (14) – atomic number (7)= 7 neutrons 7 N Nitrogen 14. 007