Question

all metal of grp 1 st and 2 nd form ionic compound except Be and Li.so why Be and Li form covalent compound?​

Answer 1

Answer:

The alkali metals consist of the chemical elements lithium (Li), sodium (Na), potassium (K),[note 1] rubidium (Rb), caesium (Cs),[note 2] and francium (Fr). Together with hydrogen they comprise group 1,[note 3] which lies in the s-block of the periodic table. All alkali metals have their outermost electron in an s-orbital: this shared electron configuration results in their having very similar characteristic properties.[note 4] Indeed, the alkali metals provide the best example of group trends in properties in the periodic table, with elements exhibiting well-characterised homologous behaviour. This family of elements is also known as the lithium family after its leading element.

Alkali metals

Hydrogen

Helium

Lithium

Beryllium

Boron

Carbon

Nitrogen

Oxygen

Fluorine

Neon

Sodium

Magnesium

Aluminium

Silicon

Phosphorus

Sulfur

Chlorine

Argon

Potassium

Calcium

Scandium

Titanium

Vanadium

Chromium

Manganese

Iron

Cobalt

Nickel

Copper

Zinc

Gallium

Germanium

Arsenic

Selenium

Bromine

Krypton

Rubidium

Strontium

Yttrium

Zirconium

Niobium

Molybdenum

Technetium

Ruthenium

Rhodium

Palladium

Silver

Cadmium

Indium

Tin

Antimony

Tellurium

Iodine

Xenon

Caesium

Barium

Lanthanum

Cerium

Praseodymium

Neodymium

Promethium

Samarium

Europium

Gadolinium

Terbium

Dysprosium

Holmium

Erbium

Thulium

Ytterbium

Lutetium

Hafnium

Tantalum

Tungsten

Rhenium

Osmium

Iridium

Platinum

Gold

Mercury (element)

Thallium

Lead

Bismuth

Polonium

Astatine

Radon

Francium

Radium

Actinium

Thorium

Protactinium

Uranium

Neptunium

Plutonium

Americium

Curium

Berkelium

Californium

Einsteinium

Fermium

Mendelevium

Nobelium

Lawrencium

Rutherfordium

Dubnium

Seaborgium

Bohrium

Hassium

Meitnerium

Darmstadtium

Roentgenium

Copernicium

Nihonium

Flerovium

Moscovium

Livermorium

Tennessine

Oganesson

noble gases ← → alkaline earth metals

IUPAC group number 1

Name by element lithium group

Trivial name alkali metals

CAS group number

(US, pattern A-B-A)

IA

old IUPAC number

(Europe, pattern A-B)

IA

↓ Period

2

Image: Lithium metal stored under paraffin

Lithium (Li)

3

3

Image: Sodium metal

Sodium (Na)

11

4

Image: Potassium metal

Potassium (K)

19

5

Image: Rubidium metal in a glass ampoule

Rubidium (Rb)