atoms, elements and compounds Flashcards
what is the relative mass of protons and neutrons
proton- 1
neutron - 1
what is the relative mass of electrons
1/ 1840
what is the atomic number or proton number
The atomic number (or proton number) is the number of protons in the nucleus of an atom.
what is the nucleon or mass number
Nucleon number (or mass number) is the total number of protons and neutrons in the nucleus of an atom
in the periodic table, what position is the mass number and atomic number on
mass number= top
atomic number = bottom
Think MASS = MASSIVE, as the mass number is always the bigger of the two numbers, the other smaller one is thus the atomic / proton number.
what is the mass number
number of nucleons in a nucleus
how are elements arranged in the periodic table
Elements are arranged on the Periodic table in order of increasing atomic number where each element has one proton more than the element preceding it
what are groups and periouds
ertical columns called Groups numbered I – VIII and in rows called Periods
what simmilar characteristics do elements in the same group share
Elements in the same group have the same amount of electrons in their outer shell, which gives them similar chemical properties
what are isotopes
Isotopes are atoms of the same element that contain the same number of protons and electrons but a different number of neutrons.
what are the two categories of isotopes
radioactive and non-radioactive
what are radiocative isotopes
Radioactive isotopes (radioisotopes) are unstable due to the imbalance of neutrons and protons, which causes the nucleus to decay over time through nuclear fission and emit radiation.
what are the medical uses of radioactive isotopes
- treat cancer
2. sterelization
what are the industral uses of radioactive isotopes
- radioactive dating
- detect leaks
- used as nuclear in power plants
why do isotopes share properties
because they have the same number of electrons in their outer shells and this is what determines an atom’s chemistry
The difference between isotopes is the neutrons which are neutral particles within the nucleus and add mass only
how is energy related to the nucleus
The further away from the nucleus then the more energy a shell has.
what is the valance shell
The outermost shell of an atom is called the valence shell and an atom is much more stable if it can manage to completely fill this shell with electrons
what is an element
A substance made of atoms that all contain the same number of protons (one type of atom) and cannot be split into anything simpler
what is a compound
A pure substance made up of two or more elements chemically combined
how can compounds be seperated
Compounds cannot be separated into their elements by physical means
what is a mixture
A combination of two or more substances (elements and/or compounds) that are not chemically combined
how can mixtures be separated
Mixtures can be separated by physical methods such as filtration or evaporation
name 4 properties of metals
- Conduct heat and electricity
- Are malleable and ductile (can be hammered and pulled into different shapes)
- Tend to be lustrous (shiny)
- Have high density and usually have high melting points
name four properties of nonmetals
- Do not conduct heat and electricity
- Are brittle and delicate when solid and easily break up
- Tend to be dull and nonreflective
- Have low density and low melting points (many are gases at room temperature)
