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Notes from Biology notes for EOC test
description "Notes from Biology for EOC test"
Everything in the universe is composed of...
Anything that occupies space oe has mass
An element is...
A pure substance that cannot be broken down chemically into simpler kinds of matter
There are more than ______ elements
90% of mass of an organism is composed of 4 elements, what were they?
Oxygen, carbon, hydrogen, & nitrogen
The simplest particles of an element that retains all the properties of that element
What consist of an atom?
Protons, Neutrons, and Electrons
- central core
- consists of positive (+) charged protons & neutral neutrons
- positively charged
- contains most of the mass of the atom
All atoms have the same number of...
Number of protons called...
The atomic number
Number of electrons is...
balanced by an equal # of electrons
Number of neutrons varies slightly among..
Atoms of the same element
Protons and Neutrons have a mass of...
1 amu (atomic mass unit)
Atomic mass =
Protons and Neutrons
Negatively charged high energy particles with little or no mass
How many energy levels dotes an atom have?
The levels are
K (closest to nucleus), L, M, N, O, P, Q (farthest to nucleus)
Level K can only hold ___ ; Levels L to Q can hold ____
2 ; 8