Groups Of The Periodic Table Flashcards
(26 cards)
What is a group in the periodic table?
A vertical column where elements have the same number of electrons in their outer shell.
What do elements in the same group have in common?
Similar chemical properties and the same number of outer electrons.
How many groups are there in the periodic table?
8 main groups (Group 1 to Group 0 / 18 in modern numbering).
What are Group 1 elements called?
Alkali metals.
What is a key property of alkali metals?
They are very reactive, especially with water.
What do alkali metals form when reacting with water?
A metal hydroxide and hydrogen gas.
Example: 2Na + 2H_2O \rightarrow 2NaOH + H_2
How does reactivity change down Group 1?
It increases.
Why does Group 1 reactivity increase down the group?
Outer electron is further from the nucleus and more easily lost.
What is the appearance of alkali metals?
Soft, shiny (when freshly cut), low melting points.
What are Group 7 elements called?
Halogens.
What kind of ions do halogens form?
Negative ions (anions), by gaining one electron.
How does reactivity change down Group 7?
It decreases.
Why does reactivity decrease down Group 7?
Atoms get larger and it’s harder to attract an extra electron.
What is a displacement reaction involving halogens?
A more reactive halogen displaces a less reactive one from a solution of its salt.
Example: Cl_2 + 2KBr \rightarrow 2KCl + Br_2
What state are halogens at room temperature?
Varies: Fluorine (gas), Chlorine (gas), Bromine (liquid), Iodine (solid).
What are Group 0 elements called?
Noble gases.
Why are noble gases unreactive?
They have full outer electron shells.
What is the trend in boiling points down Group 0?
Boiling points increase.
What are some uses of noble gases?
Helium in balloons, neon in lights, argon in welding.
Why is helium used in balloons instead of hydrogen?
It is non-flammable.
Why do elements in the same group react similarly?
They have the same number of outer shell electrons.
What determines an element’s group number?
The number of electrons in its outer shell.
What is the outer shell electron number in Group 2 elements?
Two electrons.
What kind of ions do Group 2 elements form?
2+ ions (by losing two electrons).
