A New Model By 1925, Bohr’s model was in need of some remodeling With some new information, other scientists proposed a model where electrons behaved more like waves on a vibrating string than particles circling the nucleus in an orderly fashion e- e- e-

Today, electrons are nearly impossible to exactly pinpoint in an atom because they move so fast Think of how fast the blades of a fan rotate- can you pick out just one? Therefore, all scientists can do is predict the location of an electron at any given moment, and use shading to do so The darker the shading, the more likely it is to find an electron- the shaded region is called and electron cloud

Where are Electrons Most Likely to be Found?

Electrons are found in regions called orbitals An orbital is an area of an atom where there is a high chance of finding an electron There are 4 types of orbitals: s, p, d, and f

s orbital The s orbital is the simplest one- it is shaped like a sphere and surrounds the nucleus It can hold a maximum of 2 electrons This is the lowest-energy orbital

p orbital The p orbital is a little more complex, and has 3 dumbbell-shaped regions that surround the nucleus Each dumbbell region can hold 2 electrons- with 3 regions, that’s 6 total electrons that can fit in the p orbital This orbital has a little more energy than the s orbital

d and f orbitals The d orbital is made of 5 regions- if each area holds 2 electrons, how many total electrons can fit in the d orbital? The f orbital is the most complex, and is made of 7 regions- each can hold 2 electrons for a total of 14 electrons in the f orbital d has more energy than the p orbital, and f has the most energy of the 4

Electrons always fill the s orbital first, then p, d, and lastly f This is in order of energy! Remember: the s orbital has the least amount of energy, and f has the most

Valence Electrons The outermost electrons of an atom are called the valence electrons These electrons are found in the energy level furthest from the nucleus

Lab Day- Electron Orbital Activity