Alkaline earth metal
what is an atom?
the smallest particle of an element that retains the identity of the element
what is an electron?
- a negatively charged particle within the atom
- (written e-)
- on energy level
what is a subatomic particle?
a particle that is smaller than the atom
what is the nucleus?
- in chemistry, the positivley charged centre of an atom
- is comprised of protons and neutrons
what is a proton?
- a positively charged particle that is part of every atomic nucleus
- same amount of protons as electrons in an atom
- (written p+)
what is a neutron?
- an uncharged particle that is part of almost every atomic nucleus
- neutral charge
- atomic mass-atomic number=number of neutrons
- (written n0)
what are energy levels?
- a possible level of energy an electron can have in an atom
- an electron must absorb energy to move up a level
what is an atomic number?
the number of protons in the nucleus of an atom or the number of electrons
what is a mass number?
- the sum of the number of protons and the number of neutrons in the nucleus of an atom
what is an isotope?
- one of two or more forms of an element that have the same number of protons but a different number of neutrons
- is the reason for decimals on mass numbers
what is the bohr-rutherford diagram?
- indicate number of protons and neutrons in nucleus
what is atomic mass?
- the average mass of the naturally occuring isotopes of an element
- elements are placed in order of increasing atomic mass on periodic table.
- number of protons and neutrons in nucleus
what is the periodic table?
- a system for organizing the elements into columns and rows, so elements with similar properties are in the same column
what is a metal?
- typically, an element that is hard, shiny, malleable, and ductile, and is a good conductor of heat and electricity
- eg. copper, nickel
what is a non metal?
- typically, an element that is not shiny, malleable or ductile, and is a poor conductor of heat and electricity
- eg.bromine, oxygen
what is a metalloid?
- an element that shares some properties with metals and some properties with non metals
- eg. antimony, silicon
what is a period?
- a horizontal row of elements in the periodic table
- numbered from 1 to 7
what is a group?
- a vertical column of elements in the periodic table
- numbered from 1 to 18
- also called a family
- have very similar physical and chemical properties
what is a valance electron?
an electron in the outermost occupied energy level of an atom
what are Alkali Metals?
- the elements in group 1(except for hydrogen).
- have low melting points
- soft enough to be cut with a knife
- highly reactive with water and oxygen
- eg. lithium, sodium, potassium
what are alkaline earth metals?
- elements of group 2
- highly reactive, but less than alkali metals
- if heated, will burn in air- combustible
- often used in fireworks
- produce bright flames
- eg. beryllium, magnesium, calcium
what are halogens?
- elements of group 17
- highly reactive
- extremely corrosive
- melting points increase as you move from top to bottom of group
eg. gases are; florine, bromine, liquid is bromine, iodine is solid at room temperature
what are noble gases?
- elements of group 18
- main property is non reactivity
- non metals
- odorless, and colourless at room temperature
- eg.helium, neon, xenon