Chapter two Flashcards
(13 cards)
What is matter?
Matter is anything that takes up space and has mass
What is an element?
An element is substance that cannont be broken down to simpler substances by chemical reactions
What is a compound?
A compound is a subtance made up of two or more different elements combined in a fixes ratio
What is the percentage of essential elements?
It is around 20-25%
What are the main elements?
They are O, C, H, and N making up to 96% of living matter. The other about 4% consists in Ca, K, P and S
What are trace elements?
Trace elements are elements required by an organism only in a small quantity such us iron and iodine
What is an Atom?
It is the smallest unit of matter that still retain the properties of an element
What is the Mass number?
It is the total number of protons and neutron and it is written up in the left part
What is the Atomic number?
It is the total number of electons in a neutral atom
What is an isotope?
It is a different atomic form of the same element
What is a radioactive isotope?
It is an isotope in which the nucleus decays spontaniously
What is energy?
It is the capacity to cause change
What is potential energy?
It is the enrgy that matter posses because of its location or structure
