TOPIC Electrons in Atoms GroundExcited States Do Now
- Slides: 20
TOPIC: Electrons in Atoms Ground/Excited States Do Now: Draw Bohr’s Model for Argon
Cathode Ray Tubes & Discovery of Electrons Movie of cathode ray tube
Thomson’s Plum-Pudding Model The positive charge is evenly smeared out. The negative charge is in bits – like chips. source
Rutherford’s Experiment - 1911 source
Problems with the Rutherford Model • Why don’t electrons crash into nucleus? • How are electrons arranged? • Why do different elements exhibit different chemical behavior?
Bohr Model • Bohr - electrons in atom can have only specific amounts of energy NEW idea! • Each specific energy is associated with specific orbit – --electrons are restricted to these orbits
Bohr assigned quantum number (n) to each orbit the smallest orbit (n= 1) is closest to nucleus has lowest energy larger the orbit, more energy it has Highest energy (least stable) n=3 n=2 n=1 Lowest energy (most stable)
Max Capacity of Bohr Orbits Orbit Max # of Electrons 1 2 2 8 3 18 4 32 n 2 n 2
energy levels get closer together the farther away they are from nucleus Larger orbits can hold more electrons
Electron Transitions • EXCITED STATE: • If electron gains (absorbs) specific amount of energy it can be excited to higher energy level (farther from nucleus – less stable) Endothermic process GROUND STATE: Energy released when electron: drops to lower orbit (closer to nucleus – more stable) Exothermic process
Ground State vs. Excited State • Ground state: – Lowest energy state of atom – electrons in lowest possible energy levels • Configurations in Reference Tables are ground state • Excited state: – Many possible excited states for each atom – One or more electrons excited to higher energy level
Ground State comes from the reference table Ar = 2 -8 -8 Total number of electrons = 18 Total number of protons = 18 Atomic Number = 18
Excited State comes from the reference table 2 -8 -7 -1 Total number of electrons = 18 Total number of protons = 18 Atomic Number = 18 Look on the periodic table for the atomic number 18, what is the ground state electron configuration
Which principal energy level of an atom contains electron with the lowest energy? a) b) c) d) A) n=1 B) n=2 C) n=3 D) n=4
What is total # of occupied principal energy levels in atom of neon in ground state? a) b) c) d) A) 1 B) 2 C) 3 D) 4
Which atom in ground state has five electrons in its outer level and 10 electrons in its kernel? a) b) c) d) A) C B) Cl C) Si D) P Kernel electrons = inner electrons
Which electron configuration represents atom in excited state? A) 2 -8 -2 a) B) 2 -8 -1 b) C) 2 -8 c) D) 2 -7 -1
Which electron configuration represents atom of Li in an excited state? a) b) c) d) A) 1 -1 B) 2 -0 -1 C) 2 -1 D) 2 -2
- Periodic table of elements regents
- Chapter 5 review arrangement of electrons in atoms
- Diamagnetic elements
- 5 electrons in atoms
- Electrons in atoms section 3 electron configuration
- Electrons in atoms section 2 quantum theory and the atom
- Atoms tend to gain lose or share electrons
- How to find the electrons in periodic table
- Chapter 4 arrangement of electrons in atoms test
- Electrons in atoms section 1 light and quantized energy
- How do chemists model the valence electrons of metal atoms?
- Electrons in atoms section 1 light and quantized energy
- Chapter 5 electrons in atoms
- Atoms with 4 valence electrons
- Ionic and metallic bonding chapter 7 practice problems
- Lowest allowable energy state of an atom
- Collision theory states that
- Now i see it now you don't
- Narrow topic examples
- Example of a clincher
- Paragraph "topic sentence" states