1.6 periodic table flashcards

Question 1

definition of an element

Answer 1

a substance that contains only one type of atom and cannot be broken down into anything chemically simple

Question 2

Mendeleev and the periodic table

Answer 2

Russian scientist, Demetri Mendeleev in 1869, his key to success was realization that previous attempts had failed because a number of elements were as yet undiscovered and that gaps must be left for such elements in the classification
he wrote down what he knew about each element on a separate card then sorted card into piles brining together elements which had features in common. Then he laid out cards in rows, in order of atomic mass

he noticed he needed to start a new row with every 8th element. in each row there was a pattern in properties of element from the metal to the non metal , Mendeleev called this periodic variation in the properties and that is how the table got its name

Question 3

what is the fundamental difference between the modern periodic table and Mendeleev’s

Answer 3

Mendeleev arranged the elements in order of increasing atomic mass. Modern table in order of increasing atomic number

Question 4

other key differences between modern periodic table and Mendeleev’s

Answer 4

more elements/ no gaps in modern periodic table
separate block for transition metals in the modern periodic table
noble gases have been discovered and are present in the modern periodic table
Actinides and lanthanides are present in the modern periodic table

Question 5

metals

Answer 5

good conductors of heat and electricity
ductile
malleable
high melting point
sonorous

( due to the delocalized electrons the layers of ions can slide over each other and rearrange without breaking the metallic bond)

Question 6

non metals

Answer 6

poor conductors of heat and electricity
brittle when solid
low melting points
non sonorous