CHAPTER 1 Flashcards
(23 cards)
What are all organisms made of ?
Matter
What is matter?
Anything that takes up space and has a mass and is made of elements
What are elements ?
A substance that can’t be broken down to other substances by chemical reactions
How many elements are there?
92 out of those there are 20-25 % that are essential elements
What are essential elements ?
One that an organism needs in order to remain healthy and reproduce
What are the elements all organisms need?
Oxygen, hydrogen, nitrogen and carbon
These make up 96 percent of living matter
(Remaining are Carbon ,P,K,S)
What are trace elements ?
Elements that are required by the organism in very small amounts (iron and iodine)
What are elements composed of ?
Small units of matter that still retain properties of that element also known as atoms
What are atoms composed of?
Smaller parts called subatomic particles
What are the three subatomic particles?
Neutrons (neutral charge)
Protons (positively charged )
Electrons ( negative charged)
Where are protons and neutrons found?
In the atomic nucleus
Where are electrons found ?
Surround the nucleus in a cloud
How can the number of electrons be determined?
By the atomic number
Since all atoms have a neutral charge the # of protons = the number of electrons
What is a compound ?
A substance consisting of two or more elements combined in a fix ratio, its characteristic are different from those of its elements
Where are an atoms electrons found?
Distances away from the nucleus and vary in the amount of energy the possess
What is the location electrons are found on called?
They are found on electron shells which is basically shells distances away from the nucle
Do electrons have more energy closer to the nucleus or not?
No electrons further away have more energy
What describes the chemical behaviour of an atom?
It’s defined by the electron configuration and distribution (can find the electron configuration by the periodic table )
How many electrons can each shell hold?
1= 2
2=8
3=8
Electrons fill up the lowest energy levels first
What are valence electrons?
The electrons on the outermost shell (determine the chemical behaviour of an atom)
What is the outer most shell called?
Valence shell
What does valence of an atom refer to?
The number of unpaired electrons in its valence shell
What determines if A atom is reactive ?
If the atom does not have a completed valence shell it is considered reactive
(Can combine or interact with other atoms that it comes in contact with)
