c2 Flashcards
the periodic table
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
Give 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
Give the formulae of the first four halogens.
F2, Cl2, Br2, I2
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)
