1: Scientific Method + Polarity

Chemical Bonds

Atoms with incomplete valence shells share/transfer valence electrons with certain other atoms, interactions result in atoms staying close together

Strongest to Weakest Chemical Bonds

Covalent bond, ionic bond, hydrogen bond, hydrophobic interaction, Van der Waals attraction

Covalent Bond

Sharing pair of valence electrons, shared electrons count as a part of each atom’s valence shell

Ionic Bond

Attraction of opposite electrical charges (difference in electronegativity >2)

Hydrogen Bond

Sharing on an H atom

Hydrophobic Interaction

Forcing hydrophobic substances together in presence of polar substance

Van der Waals Attraction

Weak attractions betwwen atoms due to oppositely polarized electron clouds

Molecules

Consists of 2 or more atoms held together by covalent bonds, smallest units of compound that retains characteristics of said compound

Compounds

Substance which is formed by 2 or more different types of elements which are united chemically in fixed proportion

Electronegativity

Atoms in molecule attract electrons to varying degrees, atom’s attraction for electrons in covalent bond, increases up and right, fluorine has highest, noble gases have no electronegativity

Non-polar Covalent Bonds

Atoms share electron equally, always occurs if atoms bonded together are same element (H2, O2), form between two different atoms of similar electronegativities (difference < 0.5)

Polar Covalent Bonds

1 atom more electronegative (difference between .5 to 2) + atoms don’t share electron equally, unequal sharing causes partial positive or negative charge for each atom/molecule

Polarity

Dependent on electronegativity of atoms + shape of molecule, individual bonds in CO2 polar due to unequal sharing of electrons between carbon + oxygen, 2 Oxygens pull Carbon with equal force on linear plate so net pull is 0 meaning it’s non-polar molecule

Water

Polar molecule, hydrogen + oxygen have different electronegativities, shape bent due to oxygen’s 2 unbound pairs of electrons in 2 of its hybrid orbitals

Solvent

Substance, usually liquid, that’s capable of dissolving other compounds

Polar Solvents

Water, vinegar, ethanol; dissolve other polar molecules

Non-Polar Solvents

Oil, gasoline; dissolve other non-polar molecules

Scientific Method

Process of acquiring + verifying information through experimentation

Hypotheses

Tentative/testable explanation for observation/phenomenon, basis for setting up experiments