atoms and isotopes Flashcards
what is matter ?
matter is something that has mass and occupies space.
ex: pencil, table, chair
what is an atom ?
an atom is a tiny unit of matter that is invisible to the naked eye
what is an element?
an element is the simplest form of a pure substance.
ex: carbon, helium, hydrogen etc.
what is the name for the columns of the periodic table?
Groups.
what is the name for the rows in the periodic table?
Periods.
who created the periodic table?
dmitri mendeleev.
certain groups have there own name, what are they? and what group do they belong to?
alkali metals(group 1) Alkaline metals (group 2) halogens ( group 17) noble gases ( group 18) transition metals (from group 3-12)
what was John Daltons theory?
atomic theory: all matter is made up of tiny, indivisible particles called atoms.
what did J.J Thompson’s create? and what is it?
the plum pudding model: atoms are believed to have electrons mixed together positively charged “dough”, to form a neutral ball.
what was the point of the rutherford gold experiment?
to test out the plum pudding model, to know if it was true.
what was the conclusion of the rutherford gold expirement?
that atoms have a small dense nucleus.
electrons travel outside the nucleus.
where are protons located? and what is it’s charge?
1) located in the nucleus
2) positively charged
where are electrons located? and what is its charge?
1) travel outside the nucleus
2) negatively charged
Where are neutrons located? and what is its charge?
1) in the nucleus
2) no charge ( neutral)
what is an isotope?
isotopes are atoms of same element that have different # of neutrons in their nucleus.
