Chapter 2: The Chemical Context Of Life Flashcards
What is an element?
An element is a substance that cannot be broken down into anything simpler by ordinary chemical means.
What is matter?
Matter is anything that has mass and occupies space.
What is an atom?
An atom is the smallest unit of matter that still retains the properties of an element.
What is mass number?
Mass number is the total number of protons and neutrons in an atom’s nucleus.
What is the atomic number?
The atomic number is the number of protons in the nucleus of the atom, unique to each element and designated by a subscript to the left of the elemental symbol.
What is atomic mass?
Atomic mass is the total mass of an atom, which is the mass in grams of 1 mole of an atom.
What is a molecular formula?
A molecular formula is a type of molecular notation representing the quantity of constituent atoms, but not the nature of the bonds that join them.
What is a compound?
A substance consisting of two or more different elements combined in a fixed ratio
What four natural elements make up 96% of living matter?
oxygen, carbon, hydrogen, nitrogen (highest to lowest)
What elements account for remaining 4% of an organism’s weight?
calcium, phosphorus, potassium, sulfur, sodium, chlorine, magnesium (highest to lowest)
What is a trace element?
An element indispensable for life but required in extremely minute amounts. They make up less than 0.01% of human body weight.
List some elements that are trace elements.
Boron, chromium, cobalt, copper, fluorine, iodine, manganese, molybdenum, selenium, silicon, tin, vanadium, zinc
What is the atomic mass?
The total mass of an atom, numerically equivalent to the mass in grams of 1 mole of the atom. (For an element with more than one isotope, the atomic mass is the average mass of the naturally occurring isotopes, weighted by their abundance.)
What is a compound?
A compound is a substance consisting of two or more different elements combined in a fixed ratio
What four natural elements make up 96% of living matter?
oxygen, carbon, hydrogen, nitrogen (highest to lowest)
