Chapter 2 Flashcards
Elements
are substances that cannot be broken down chemically into simpler substances.
All elements can be found where?
Periodic Table
How many elements make up the human body?
99.9%
Big 4 elements
Oxygen, Carbon, Hydrogen, Nitrogen
Atoms
smallest component of an element that cannot be subdivided further without loosing its properties
Mass number
number of protons and neutrons in the nucleus.
Atomic number
Number of protons in an atom
Isotopes
atoms with the same number of protons, but a different number of neutrons
radioactive isotopes
Isotopes that are not stable and emit radiation
When are isotopes stable?
when it has a balanced number of neutrons or protons.
Valence shell
Outermost shell with e-
How many electrons can shell 1 have
2
How many electrons can shell 2 have?
8
How many electrons can shell 3 have?
8
Inert
Non-reactive atoms, full atomic shells
Reactive
Atoms that interact with other atoms, aren’t full
Ions
Atoms with an electrical charge: positive or negative
Positively charged ions
Cations
Negatively charged ions
Anions
How do chemical bonds allow atoms to achieve stability?
creating arrangements to fill the outer shell of each atom.
Ionic Bond
Form when one or more electrons are transferred between atoms
Covalent Bonds
Formed when electrons are shared between atoms
Electrons transferred: One atom donates an e-
Gains a+ charge
One atom accepts an e-
Gains a – charge
Non polar covalent bonds
Equal sharing of electrons
Polar covalent bonds
Unequal sharing of electrons
Cohesion
water molecules’ ability to interact with each other
Adhesion
water molecules ability to interact with other molecules
Water is referred to as the what solvent?
Universal solvent
Acids
Compounds that release or donate H+ ions are called acids
Bases
Compounds that releases OH- or combines with H+
Buffers
compounds that resist changes of pH
