PERIODIC TABLE AND PERIODICITY Flashcards
(15 cards)
Group II
Beryllium (Be)
Magnesium (Mg)
Calcium (Ca)
Strontium (Sr)
Barium(Ba)
Group II react with oxygen
Group II metals burn in air and even more rapidly in oxygen
Group II react with water
Magnesium reacts slowly with cold water:
Hot magnesium reacts with steam to form magnesium oxide
Calcium react s more rapidly with water than magnesium
Group II react with hydrochloric acid
Group II metals react wit h hydrochloric acid to form hydrogen and salts called chlorides
Group II and ease of ionisation
The energy needed to remove an electron from an atom or ion is called t he ionisation energy
The reactivity of the Group II metals is linked to the ease with which they form ions.
Group VII
The Group VII elements are called the halogens. They all exist as diatomic molecules. This means that they have molecules made up of two atoms
Fluorine (F,)
Chlorine (CI,)
Bromine (Br,)
Iodine (I,)
What happens to the physical state of halogens as you go down the group
They go from gas → liquid → solid.
Fluorine & Chlorine – gases
Bromine – liquid
Iodine & Astatine – solids
What happens to colour intensity as you go down Group VII
The colour becomes darker:
Fluorine – pale yellow
Chlorine – greenish-yellow
Bromine – reddish-brown
Iodine – purple (solid)
What happens to oxidising power down the group
Oxidising power decreases.
Fluorine is the strongest oxidising agent.
Astatine is the weakest.
Why does oxidising power decrease down Group VII?
Because atoms get larger, and it becomes harder to gain electrons due to more electron shielding.
What elements are in Period 3 of the periodic table?
Sodium (Na), Magnesium (Mg), Aluminium (Al), Silicon (Si), Phosphorus (P), Sulfur (S), Chlorine (Cl), Argon (Ar).
How do the metallic properties change across Period 3
The metallic properties decrease as you go across the period.
Sodium, Magnesium, and Aluminium are metals (good conductors, malleable).
Silicon is a semi-metal (metalloid, properties between metals and non-metals).
Phosphorus, Sulfur, Chlorine, and Argon are non-metals (poor conductors, brittle).
What are semi-metallic properties in Period 3
Semi-metallic or metalloids like Silicon have both metallic and non-metallic properties.
They are conductive but not as well as metals.
Can form covalent bonds.
How do conductivity and reactivity change across Period 3?
Metals (Sodium to Aluminium): Good electrical conductors, react with oxygen and water.
Semi-metal (Silicon): Conducts electricity but not as well.
Non-metals (Phosphorus to Argon): Poor conductors, less reactive with oxygen (except for chlorine).
What is the trend in ionization energy across Period 3?
Ionization energy increases from left to right across Period 3 because atoms get smaller and more protons are added, making it harder to remove electrons
