Physical science Flashcards
In any sample of a compound, the elements composing it are always found in the same proportion by mass. - Law?
Law of definite proportions
Matter can neither be created nor destroyed during chemical reactions. Law?
Law of conservation of mass
Why did Mendeleev design the periodic table of elements?
To provide his students with a guide for memorizing the elements and their properties.
On the periodic table ________ have similar properties.
Vertical rows.
A you move from left to right across the table, the elements become more like ____ and less like _____.
nonmetals….. metals.
the only two elements in period one are _____ and _____.
hydrogen and helium.
Elements with incomplete inner electron levels are _________.
Transition elements.
Which periods contain transition elements?
Periods four, five, six and seven contain transition elements.
Elements of the __________ series are radioactive, unstable, and most do not occur naturally.
Actinide
The __________ series is in Period seven, the ___________ series is in period six,
Actinide … Lanthanide
Why are the actinide and lanthanide series found at the bottom of the periodic table?
The actinide and lanthanide series are found at the bottom of the periodic table because there is no room to place them where they belong on the table.
All the metalloids:
Boron, silicon, germanium, arsenic, antimony, tellurium, polonium.
who designed the periodic table?
Mendeleev.
