Chapter 2: Chemistry Flashcards
The smallest unit of matter is what?
An atom
Major elements in body that make up 96% of mass
Nitrogen Oxygen Carbon and hydrogen
All living and nonliving things in the body that exists in 3 states
Matter
How many chemical elements are normally present in the body ?
26
Within nucleus these are positively charged
Protons
What is an isotope?
Atoms of an element with same number of protons but different neutrons and therefore different mass number
Unstable; their nuclei decay (spontaneously change) into a stable configuration is called what ?
Radioactive isotope
An atom of a positive or negative charge because of unequal protons and electrons
Ion
What is it called when two or more atoms share electrons?
Molecule
What is a compound ?
Two or more different elements joined
What will accelerate chemical bonds, by lowering activation energy ?
Catalyst
How many electrons can the first four shells hold?
1st: 2
2nd: 8
3rd: 18
4th: 18
Weak bonds between molecules
Hydrogen bonds
Energy stored by matter do to its position
Potential energy
Type of reaction that releases more energy then it absorbs
Exergonic reaction