The periodic table Flashcards
What is an atom
the smallest part of an element that can exist
How are compounds formed
from elements by chemical reactions.
What do compounds contain
two or more elements chemically combined in
fixed proportions
What do compounds contain
two or more elements chemically combined in
fixed proportions
What did Mendeleevs table have
gaps
and
showed elements with similar chemical properties
why did mendeeleev leave gaps
For unknown elements to be discovered
What is the modern periodic table like
Elements are arranged in periods (rows)
Elements with similar properties are placed in groups (vertical columns)
What number in the periodic table is the number of shells
period number
what number in the periodc table is the number of electrons in the outer shell
group number
what number in the periodic table is the electronic structure
atomic number
do metals lose or gain electrons
lose
when metals lose electrons what type of ions do they produce
positive ions
What are the properties of metals
good conductor of electricity and heat shiny high density malleable ductile
Properties of non metals
poor conductor of electricity and heat
dull
low density
brittle
What is a mixture
consists of two or more elements or compounds not
chemically combined together
