1. Organizing the Elements

2. The New Periodic Table Song
Lyrics
Girl Singing
The Element Song
They Might Be Giants: Meet the Elements

4. Standard Standards: S8P1: Students will:
f. recognize that there are more than 100 elements and some have similar properties as shown on the Periodic Table of Elements

5. Key Concepts
How did Mendeleev discover the pattern that led to the periodic table?
What information about elements does the periodic table provide?
How are elements created?

6. Introduction
You wake up, jump out of bed, and start to get dressed. Then you ask, “Is there school today?” You run to check the calendar to see what day it is….
The Periodic Table is set up similar to that of an ordinary calendar.

7. Patterns in the Elements
By 1869, a total of 63 elements had been discovered. A few were gases and two were liquids . Most were solid metals.
Some scientists wondered if the properties of elements followed a pattern.
A Russian scientist, Dmitri Mendeleev, discovered a set of patterns that applied to all elements.

8. Mendeleev’s Work
Mendeleev knew that some elements have similar chemical and physical properties.
For example, silver and copper are both shiny metals that tarnish if exposed to air.
To find out the pattern, Mendeleev wrote each element’s melting point, density, and color on individual cards.
He also included the element’s atomic mass (protons + neutrons) and all the chemical bonds it could form (like Hydrogen connecting with Oxygen to form water).
He noticed a pattern when he arranged the elements in order of increasing atomic mass.

9. Mendeleev’s Periodic Table
Mendeleev found that properties of elements repeated.
Sodium reacted with water the same way as Lithium (Li) and Potassium (K) did.
Sodium reacts violently to Water! 4
So he placed these cards into a group and did the same for all others.

10. Predicting New Elements
Mendeleev found that arranging the known elements strictly by atomic mass did not always group similar elements together
After he arranged all 63 elements together, 3 spaces were left.
He predicted that the blank spaces would be filled by elements not yet discovered.
In 1869, Mendeleev published the first periodic table. Within 16 years, the other 3 missing elements – scandium, gallium, and germanium, had been discovered.

11. The Modern Periodic Table
“periodic” – in a regular repeated pattern.
In the early 1900’s, Henry Mosley discovered how to measure the positive charge of an atom’s nucleus – by using its atomic number. (How positive is it? By how many protons it has)
Not long after, the table was rearranged in order of atomic number, not atomic mass.
A few elements shifted position.

12. How’s It Organized?
The properties of an element can be predicted from its location in the periodic table.
The Periodic Table is organized by the atomic number (# of protons) in an element.
The table is organized by horizontal rows called periods and also by vertical columns called groups

13. A period contains a series of different elements just as a week on a calendar has different days.
Elements on the LEFT side are HIGHLY REACTIVE METALS. (PURPLE)
Elements in the MIDDLE are LESS REACTIVE METALS. (PURPLE)
Elements on the RIGHT side are METALLOIDS and NONMETALS. (YELLOW AND GREEN)
This pattern is repeated in each period.

14. Groups are sometimes called families.
Elements in Group 1 are violently reactive with water and Group 2 react slowly or not at all.

15. Reading an Element’s Square
Each square includes the element’s atomic number (number of protons), chemical symbol, and atomic mass (number of protons + neutrons in nucleus).
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16. Element Square

17. You Try!
What is this number?
What is this number?

18. How Elements Form Stars
Have you ever wondered where elements come from?
The sun is made mostly of one element – hydrogen. It burns at 15 million degrees Celsius.
At these extremes, matter does not exist as solid, liquid, or gas. Instead, it is called plasma.
Plasma – a state of matter that consists of a gas-like mixture of free electrons and nuclei of atoms that have been stripped of electrons.

19. New Elements from Fusion
When colliding nuclei (many nucleus-es colliding) have enough energy, they can combine. This combination is called nuclear fusion.
Nuclear Fusion – process in which two atomic nuclei combine, forming a larger nucleus and releasing huge amounts of energy.
Nuclear fusion combines smaller nuclei into larger nuclei and create heavier elements.