Definitions
What is the core of an atom called?
Nucleus
The word atom comes from what Greek word?
uncuttable
What is formed when two or more elements bond?
a compound
What is an atom of an element with the same number of protons but a different number of neutrons?
an isotope
How many elements occur naturally?
92
What is a positively charged particle in the center of an atom?
Proton
What makes one atom different from another?
The number of protons in the nucleus
Atoms cannot be created or destroyed by what?
physical means
Electrons are found in energy levels in the what?
electron cloud
What makes the chemicals of living things. It's the key to life.
Carbon
What is a negatively charged particle located in the atom cloud?
Electron
John Dalton was an English what?
Chemist
mass
The first energy level holds how many electrons?
2
Everything in the universe is either_______ or ______.
matter or energy
What is the number of protons in the nucleus called?
Atomic number
What did John Dalton propose in 1803?
atomic theory of matter
What is the scale that is used to measure the mass of atoms?
Atomic mass unit or (amu)
The second energy level holds how many electrons?
8
Everything that is a thing is?
matter
Everything that's a thing is....
Matter
Who was the Greek philosopher who suggested the idea of an atom?
Democritus
What is one amu equal to?
one proton
The third energy level holds how many electrons?
18
Carbon is so important that there is a whole branch of chemistry named after it. What is it called?
Organic Chemistry