Chapter 2: Chemistry Comes Alive
How many elements are recognized?
118 elements. 92 occur in nature.
Periodic table
A listing of the known elements and helps to explain the properties of each element.
Matter
Anything that occupies space and has mass.
Protons
Bear a positive electrical charge.
What four elements make up about 96% of body weight?
Carbon, oxygen, hydrogen, and nitrogen.
What form of energy is found in the food we eat?
Chemical energy
Describe the major energy forms.
Chemical energy, Electrical energy, Mechanical energy, Radiant energy or electromagnetic radiation.
Atoms
Each element is composed of essentially identical particles of building blocks.
What form of energy is used to transmit messages from one part of the body to another?
Electrical energy is the energy used by nerve cells to transmit messages to the body.
Mechanical energy
Energy directly involved in moving matter.
Kinetic energy
Energy in action.
Radiant energy or electromagnetic radiation
Energy that travels in waves.
Differentiate between matter and energy and between potential energy and kinetic energy.
Matter is anything that occupies space and has mass. Energy is defined as the capacity to do work, or to put matter into motion. Kinetic energy is energy in action. Potential energy is stored energy.
Neutrons
Neutral
What type of energy is available when we are still? When we are exercising?
Potential energy is available when we are still. When we exercise, PE is converted to kinetic (working) energy, specifically to mechanical energy.
Atomic mass unit
Protons and neutrons are heavy particles and have approximately the same mass
Electrical energy
Results from the movement of charged particles.
Potential energy
Stored energy, that is inactive energy that has the potential, or capability, to do work but is not presently doing so.
Energy
The capacity to do work, or to put matter into motion.
Nucleus
The center of the atom containing protons and neutrons tightly bound together.
Chemical energy
The form stored in the bonds of chemical substances.
Elements
Unique substances that cannot be broken down into simpler substances by ordinary chemical methods.
Atomic symbol
We designate each element by a one-or two letter chemical shorthand, usually the first letter of the element's name.