section one test Flashcards
what is an Element?
an element is a substance made of only one type of atom that cannot be separated into something simpler.
a basic structure of an atom
an atom is built up of neutrons, protons, and electrons.
compound
two or more substances that are chemically bonded
Mixture
when there are two substances are close but not chemically bonded.
Diatomic Elements
gases that form molecules because they do not have full valence shells.
Ways to remember the diatomic elements.
Have No Fear Of Ice Cold Beer. (hydrogen, nitrogen, fluorine, oxygen, iodine, chlorine, Bromine.
Atomic Number
The number of protons in the nucleus of an element. it determines its place in the periodic table.
Mass Number
The total number of protons and neutrons in an element.
Atoms why don’t they have a charge?
they have no charge because they always have the same amount of protons in the nucleus as electrons making them neutral.
Isotopes
Isotopes are elements of the same type with more neutrons than protons in its nucleus.
subatomic particles
neutron, electron, proton
AMU (Atomic Mass Number)
each subatomic particle has a weight but, it is so small they have their own unit. proton=1 AMU neutron=1Amu Electron= 1/2000 (AMU)
Ion
an atom or molecule with a net electric charge due to the loss or gain of one or more electrons. This charge can be positive or negative.
Cation
A Cation is a positively charged ion. this when an atom loses an electron to have a full valence shell.
Anion
An Anion is a negatively charged ion. this is where it has to gain electrons to have a full valence shell. E.G. hydrogen.
Why is an Ion charged?
because the element has more or fewer electrons than protons in its nucleus.
why do elements in the same group act similarly?
they act similarly because they have the same amount of electrons in their valence shells.
The maximum number of electrons in the first 4 energy levels.
2,8,8,18
Why does chlorine not have a whole mass?
it doesn’t have a whole mass number because it has two common isotopes and the RELATIVE ATOMIC MASS NUMBER comes out at 35.5 as chlorine-35(17 protons 18 neutrons) is found %75 of the time and Chlorine -37(17 protons 20 neutrons) is found %25 of the time.
typical properties of transition metals
they form colored compounds.
they are good conductors of heat and electricity.
they can be hammered or bent into shape easily.
they are less reactive than alkali metals such as sodium.
they have high melting points