C2(2.1-2.6) The Periodic Table Flashcards
How is the modern Periodic Table ordered?
-By atomic number
How were the early lists of elements ordered?
-By atomic mass
Why did Mendeleev swap the order of some elements?
-To group them by their chemical properties
Why did Mendeleev leave gaps in his Periodic Table?
-Leave room for elements that had not yet been
discovered
Why do elements in a group have similar chemical
properties?
-Have the same number of electrons in their outer shell
Where are metals and non-metals located on the
Periodic Table?
-Metals to the left, non-metals to the right
What name is given to the Group 1 elements?
-Alkali metals
Why are the alkali metals named this?
-They are metals that react with water to form an alkali
State the general equations for the reactions of alkali
metals with oxygen, chlorine, and water.
-metal + oxygen ➞ metal oxide
-metal + chlorine ➞ metal chloride
-metal + water ➞ metal hydroxide + hydrogen
How does the reactivity of the alkali metals change
down the group?
-Increases (more reactive)
Why does the reactivity of the alkali metals increase
down the group?
-They are larger atoms, so the outermost electron is
further from the nucleus, meaning there are weaker
electrostatic forces of attraction and more shielding
between the nucleus and outer electron, and it is easier
to lose the electron.
What name is given to the Group 7 elements?
-Halogens
How do the melting points of the halogens change
down the group?
-Increase (higher melting point)
How does the reactivity of the halogens change down
the group?
-Decrease (less reactive)
Why does the reactivity of the halogens decrease
down the group?
-They are larger atoms, so the outermost shell is
further from the nucleus, meaning there are weaker
electrostatic forces of attraction and more shielding
between the nucleus and outer shell, and it is harder to
gain an electron.
