Basics of Chemistry Week 4 Dr. Thornton OAPB

The Atom by Niels Bohr The Bohr Model electron (negative charge) shell proton (positive charge) nucleus neutron (no charge) Label Edit Figure 2.2 Representations of Atoms Hydrogen (H) Helium (He) 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 Figure 2.5 Same Element, Different Forms

Figure 2.6 Electron Configurations in Some Representative Elements

electron transfer sodium ion (Na+) chloride ion (CI–) Label Edit Figure 2.9b Electron transfer

Figure 2.9 Ionic Bonding

Figure 2.13 Complex Binding

Figure 2.7b One water molecule

ATOM ACTIVITY!

Polar Molecules Figure 2.7 Covalent Bonding

Figure 2.8a Polar water molecule

Figure 2.10 Hydrogen Bonding

Figure 2.16a Walking on Water

Figure 2.16b Beading up

In ice, the maximum number of hydrogen bonds form, causing the molecules to be spread far apart. Label Edit Figure 2.15 Life Made Possible under the Ice liquid water In liquid water, hydrogen bonds constantly break and re-form, enabling a more dense spacing than in ice.

Figure 2.14 Water’s Power as a Solvent

(a) Starting with pure water Pure water is a “neutral” substance in terms of its pH levels. Label Edit Figure 2.18a Starting with pure water (H2O)

Figure 2.18b Making water more acidic

(c) Making water more basic NaOH 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. NaOH base Label Edit Figure 2.18c Making water more basic

(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), forming water and keeping the solution at a neutral pH. Label Edit Figure 2.18d Combining acidic and basic solutions neutralized solution

Figure 2.18 Hydrogen ions and pH

Figure 2.18 Hydrogen ions and pH

Figure 2.18 Hydrogen ions and pH

Figure 2.18 Hydrogen ions and pH

Figure 2.19 Common Substances and the pH Scale