Chapter 2 Chemistry Flashcards
What is Matter?
Anything that occupies space and has mass.
What is an element?
A substance which cannot be broken down into other substances by chemical reactions.
What are the four elements that make up more than 96% of the elements in living things?
Oxygen
Carbon
Hydrogen
Nitrogen
What is a trace element?
(14 elements for humans) not required by all life
Makeup of an atom: proton, neutron, electron charges and locations in the atom
Proton (+) and Neutrons (=) are located within the nucleus. Electrons (-) are in a cloud surrounding the nucleus.
What does the number of protons tell us about an atom?
All atoms of a particular element have the same unique number of protons.
What does the number of neutrons tell us about an atom?
It tells us the mass of an atom when combined with the number of protons
What are radioisotopes?
These are unstable isotopes that give off radioactivity.
What does the number of electrons tell us about an atom?
Configuration of electrons determines the chemical properties of an element (interactions).
What is an ion?
Charged atom or molecule due to loss or gain of an electron.
What are ionic and covalent bonds?
Ionic Bonds: Attraction by oppositely charged ions
Covalent bond: Atoms share electrons to form a molecule
What is a molecule?
Two or more atoms attached by covalent bonds
What is a chemical compound?
Two or more elements in a fixed ratio
What are hydrogen bonds?
Weak bonds associated with attractions among polar molecules
What is electronegativity?
A measure of the tendency of an atom to attract a bonding pair of electrons. Some elements, such as oxygen, hold a stronger attraction for electrons than others, such as hydrogen.
