Embed Size (px)
Transcript of Periodic table
- 1. PERIODIC TABLE Chemistry Part 2
- A knowledge of chemistry is essential for understanding the structure and function of animals because body functions involve chemical reactions.
- Matter is anything that occupies space and has mass.
- Elements Pure substances that cannot be broken down into simpler units.
- Atomsare composed of a nucleus and an electron cloud.
- Nucleus central core of an atom and is made up ofProtons(particle with a positive charge) andNeutron (particle without a charge, its neutral)
- Electron cloud electrons around the nucleus
- Electrons particle with a negative charge
7. Periodic Table
- Atomic number = number of protons
- Atomic Mass=
- Total numbers
- Of protons plus
- Neutrons in
- Same atoms; different numbers of neutrons, therefore different atomic mass.
- Examples:Carbon 12 and Carbon 14
- Carbon Atomic Number 6, so how many neutrons in Carbon 12?
- Carbon 14?
- Unstable Isotopes
- Unstable nuclei, which tend to undergo radioactive decay.
- Carbon 14 is unstable isotope. (half-life of 5,730 years)
- Carbon 12 is stable.
- Energy levels different locations of electrons around the nucleus
- First level 2 electrons
- Second & all other levels 8 electrons
- The amount of electrons in the outermost energy level leads to properties of the atom will it react with other atoms?
12. Valence Electrons
- Number of electrons in outermost shell.
- If the outer shell is full then NO REACTION!
- Column 8, valence shell has 8 electrons, it is full, NO REACTION!!
- Columns 1-7?
- Fill in info on periodic table.
13. 14. Electron Dot Diagram
- Illustrates energy levels and the number of electrons in all shells.
- Can put symbol in center to represent nucleus.
- Easy way to determine number of valence electrons.
15. 16. Lewis Dot Structure
- Write symbol for element.
- Indicate valence electrons by putting dots representing electrons found in OUTER SHELL ONLY. (only show electrons that are available for bonding)
17. uc 18. Covalent Bonds
- Atoms SHARE electrons.
- Use Lewis Dot Structures
19. Ionic Bonds
- Electrons TRANSFER of electrons.
- Use Lewis Dot Structure