6. Figure 2.5 Two simplified models of a helium (He) atom
7.
8. LE 2-4a 2 2 2 Protons Neutrons Electrons Helium atom Mass number = 4 6 6 6 Protons Neutrons Electrons Carbon atom Mass number = 12 Electron cloud Nucleus 2e – 6e –
9. Figure 2.10 Electron configurations of the first 18 elements
35. LE 2-15 Acidic solution OH H H H H OH H H H OH OH OH OH OH H H H H H H Increasingly ACIDIC (Higher concentration of H ) Neutral solution OH OH OH OH OH OH H H Basic solution NEUTRAL H pH scale Lemon juice, gastric juice Grapefruit juice, soft drink Tomato juice Human urine Pure water Human blood Seawater Milk of magnesia Household ammonia Household bleach Oven cleaner Increasingly BASIC (Lower concentration of H )