Chapter 2 Flashcards
(178 cards)
Life
ability to replicate and by the presence of some sort of metabolic activity
Biodiversity
variety and variability among all genes, species, and ecosystems
Element
substance that can’t be broken down into any other substances
Everything (matter) is made up of:
atoms
atom
a particle of matter that can’t be further subdivided without losing essential properties
what are the three parts of an atom?
nucleus, and three other parts: electrons, protons, and neutrons
mass
The amount of matter in a particle
electrons weight almost:
nothing; they weight 1/20th of one percent
atomic mass
combined mass of all of the atom’s protons and neutrons
Particles that have the same charge ___ each other
repel
Particles with opposite charges are _____ to each other
attracted
How can we tell elements apart?
by their atomic number, which means how many PROTONS are in the nucleus
Elements differ in their number of ____
protons
element symbol
abbreviation of the element’s name
The mass of an atom is often about double the element’s atomic number
example:
Oxygen mass: 15.99
atomic number: 8
Isotopes
Atoms with the same atomic number (number of protons), but different numbers of neutrons
(extra neutrons or fewer neutrons than the number of protons)
(same protons, different neutrons)
in isotopes, does the charge change? Why?
-no because neutrons don’t have a charge
Does the atom’s mass change in isotopes?
yes, with the loss or addition of another particle in the nucleus
Radioactive
elements/isotopes having an unstable nucleus, breaking down spontaneously, releasing tiny, high-speed particles that carry a lot of energy.
Radioactive atoms turn out to be useful in determining what?
the age of fossils
Of all the elements found on earth, how many are found in your body?
25
The “Big 4” elements consist of:
oxygen, carbon, nitrogen, hydrogen
The “Big 4” make up how much of our body mass?
more than 96%
ions
electrically charged atoms
-number of protons are same, but number of electrons are different