Lecture 2 - Atoms And Bonds. Learning Objectives: Chapter 2.1-2.2 Flashcards
Define element and matter.
- All organisms are composed of matter. It is anything that takes up space and has mass.
- Matter is made up of elements. Elements can’t be broken down by chem reactions.
What are the four most abundant elements in the human body?
Carbon, Hydrogen, Nitrogen, Oxygen
What does an atom’s atomic number represent?
The number of protons in an atom.
Define an isotope and an ion, and differentiate between the two.
Isotopes: two atoms of an element that differ in number of neutrons. Therefore, isotopes will have the same atomic number but different mass number.
Ions: are charged atoms, that have lost or gained electrons.
Define and explain electron orbitals.
Electrons occupy orbitals,
Orbitals: regions of space where an electron spends most of is time.
Define and describe the 4 types of chemical bonds used to make molecules.
Covalent:
- In covalent bonding, molecules are formed when two atoms share their valence electrons with each other.
Polar covalent:
- Polar covalent bonding is the unequal sharing of electrons. This involves electronegativity, which is the ability of an atom to attract electron.
Hydrogen bonding:
- interaction btwn H and an electronegative atom.
- in cells usually involves, oxygen and nitrogen.
- i.e.) in water: forms, when the partial positive of H atoms are attracted to the partial negative of oxygen atoms.
Ionic:
- interaction between oppositely charged ions.
- can involve the atoms being so different in electronegativity, that the more electronegative atom strips the other of an electron completely.
Differentiate between covalent and polar covalent bonds.
Nonpolar covalent bonds are a type of chemical bond where two atoms share a pair of electrons with each other. Polar covalent bonding is a type of chemical bond where a pair of electrons is unequally shared between two atoms.
