Chapter 2.1.1 (Exam 1) Basic Chem Flashcards
An Element’s Atomic Structure Determines Its Properties
What is all matter composed of?
Atoms, which are composed of three subatomic particles
What are atoms composed of?
Protons: weigh 1 Dalton and have a +1 charge
Neutrons: weigh 1 Dalton and have neutral charge
Electrons: weigh 1/2000th of a Dalton and have a -1 charge
What is 1 Dalton in grams?
1.7 x 10-24
Generally, atoms are electrically neutral. What does this mean?
The # of protons is = to the # of electrons
What is an element?
A fundamental substance containing only one kind of atom
What is the atomic number?
The number of protons in the nucleus of the atom
Can be used to identify elements
What is an element’s behavior in chemical reactions determined by?
The number of protons and electrons
Which 6 elements constitute a majority of living tissue?
CHONPS
Carbon
Hydrogen
Oxygen
Nitrogen
Phosphorous
Sulfur
What is the mass number?
of protons + # of neutrons
What are isotopes?
Forms of an element with different numbers of neutrons, and thus different mass numbers
Biological molecules are mostly 12C, but some are 13C. What is the application of this in modern science?
The ratio of 13C:12C varies with location and can be used to identify the origin of biological samples
Name each hydrogen isotope and their mass number and atomic number.
Protium: 11H
Deuterium: 12H
Tritium: 13H
What are unstable isotopes called and what do they do?
Radioisotopes undergo radioactive decay
What is radioactive decay?
When unstable atoms give off energy in the form of alpha, beta, and gamma radiation from the nucleus
What is the effect of radioactive decay?
The atom is transformed, sometimes to a different element
What is one usage of radioisotopes in modern science?
Radioisotopes can be incorporated into molecules to act as a tag or label
What is a molecule?
A stable association of atoms
