Basics of Chemistry

Basics of Chemistry

Week 4

Dr. Thornton

OAPB

electronshell

nucleus

Hydrogen (H) Helium (He)

neutron(no charge)

proton(positive charge)

electron (negative charge)

The Atom by Niels Bohr

The Bohr Model

Electron Shells

Elements

• Matter: takes up space, has weight.

• Mass: the quantity of matter in a given object.

• Energy: review the types of energy.

Isotopes

electrontransfer

sodium ion (Na+) chloride ion (CI–)

ATOM ACTIVITY!

Polar Molecules

ice

In ice, the maximum numberof hydrogen bonds form,causing the molecules to bespread far apart.

liquidwater

In liquid water, hydrogenbonds constantly break andre-form, enabling a moredense spacing than in ice.

pure water

(H2O)

(a) Starting with pure water

Pure water is a “neutral”substance in terms of itspH levels.

(c) Making watermore basic

An equal concentration of sodium hydroxide, poured into water, dissociates into Na+ and OH– ions, moving the water toward the basic end of the scale.

base

NaOH

neutralized solution

(d) Combining acidic and basic solutions

When the acid and base solutions are poured together, the OH– ions from (c) accept the H+ ions from (b), formingwater and keeping the solution at a neutral pH.