Chapter 1 Flashcards
what are organisms composed of?
matter
what is matter?
matter is anything that occupies space/volume and has mass
what is matter made up of? and what are they?
elements; substances that cannot be broken down into simpler substances by chemical reactions
how many naturally occurring elements are there? how many elements are there at all?
there are 92 naturally occurring elements but 118 in the periodic table
what is an essential element and what % of the elements are considered essential elements?
essential elements are those that an organism requires in order to remain healthy and reproduce.
20-25% of the elements in the periodic table are considered essential elements
what are the 4 main elements in the human body?
oxygen, carbon, hydrogen, and nitrogen
what elements make up 96% of living matter?
oxygen, carbon, hydrogen, and nitrogen
what are trace elements and some examples?
trace elements are the elements that are only required by the organism in very small amounts.
iron and iodine
what elements make up the other 4%?
calcium ,phosphorus, potassium, sulphur, sodium, chlorine, magnesium
what is the effect of iodine deficiency?
goiter: enlarged thyroid gland
what is the effect of nitrogen deficiency?
reduced crop yields, low quality produce, reduced soil fertility
which is not a trace element in the body? iodine, iron, zinc, calcium, fluorine
calcium
what is an element composed of?
elements are composed of building blocks called atoms.
atoms are composed of?
smaller parts called subatomic particles.
what are the subatomic particles of an atom?
neutrons: no electrical charge
protons: positively charged
electrons: negatively charged
where are protons and neutrons found?
atomic nucleus
where are electrons found?
surround the nucleus in shells
what is the atomic number determined by?
the number of electrons an element has determines its atomic number.
what is a compound?
a compound is a substance consisting of two or more elements joined by chemical bond: has characteristics different from those of its elements individually
are electrons found at similar distances away from a nucleus?
no, electrons are found at different distances away from the nucleus of an atom.
explain a bit about electron shells.
so first is the nucleus and then there is the first shell(2 electrons) then second shell(8 electrons) and then third shell(8 electrons).
which electrons have more energy?
the electrons that are further away from the nucleus have more energy.
which shell do electrons fill up first?
the lowest energy levels first: first shell
what are valence electrons/shell?
the electrons in the outermost shell are called valence electrons. the outermost shell is called the valence shell
