Metals are an excellent conductor of electricity and heat because the atoms in the metals form a matrix through which outer electrons can move freely. Instead of orbiting their respective atoms, they form a sea of electrons that surround the positive nuclei of the interacting metal ions.

Metals are good conductors of heat and electricity because the delocalized electrons are mobile. As the temperature increases, electrical conductivity decreases because the metal atoms vibrate more, causing them to collide more with the electrons.

Most metals are very good conductors. However, even an insulating material can be a very good conductor. Semiconductors are insulators which require relatively low energies in order to “kick” the electrons to a conduction state. When electrons become “free”, the conductivity of semiconductor rises.

Silver and copper are the two best conductors of heat and electricity. Lead is the poorest conductor of heat. Bismuth, mercury and iron are also poor conductors. Density: Metals have high density and are very heavy.

While calcium is a poorer conductor of electricity than copper or aluminium by volume, it is a better conductor by mass than both due to its very low density.

Alkaline-earth metals: The alkaline-earth metals make up Group 2 of the periodic table, from beryllium (Be) through radium (Ra). Each of these elements has two electrons in its outermost energy level, which makes the alkaline earths reactive enough that they’re rarely found alone in nature.

Group 13 is called the boron group, and boron is the only metalloid in this group. The other group 13 elements are metals. Group 14 is called the carbon group. This group contains two metalloids: silicon and germanium.

Beryllium, magnesium, calcium, strontium, barium and radium are the elements in Group 2. For two reasons, these elements are referred to as Alkaline Earth metals, Their oxides remain in the crust of the earth and are very heat-stable.

Lr. Group 2A (or IIA) of the periodic table are the alkaline earth metals: beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).

Lr. Group 3A (or IIIA) of the periodic table includes the metalloid boron (B), as well as the metals aluminum (Al), gallium (Ga), indium (In), and thallium (Tl). Boron forms mostly covalent bonds, while the other elements in Group 3A form mostly ionic bonds.

Hydrogen

Halogen

The halogens are located on the left of the noble gases on the periodic table. Because the halogen elements have seven valence electrons, they only require one additional electron to form a full octet. This characteristic makes them more reactive than other non-metal groups.

Chalcogens means ore forming, as most of the ores in the earth crust are either oxides or sulphides, group 16 elements are called chalcogens. for example: Oxygen is the most abundant of all the elements on earth. Oxygen forms about 46.6% by mass of earth’s crust.

Halogens are highly reactive, and they can be harmful or lethal to biological organisms in sufficient quantities. This reactivity is due to high electronegativity and high effective nuclear charge. Halogens can gain an electron by reacting with atoms of other elements.

FLUORINE

The noble gases are a group of chemical elements that make up Group 18 on the periodic table. The six noble gases that occur naturally are helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe), and Radon (Rn).

Halogens are nonmetals in group 17 (or VII) of the periodic table. Down the group, atom size increases. As a diatomic molecule, fluorine has the weakest bond due to repulsion between electrons of the small atoms. Due to increased strength of Van der Waals forces down the group, the boiling points of halogens increase.

To obtain an octet, these atoms form three covalent bonds, as in NH3 (ammonia). Oxygen and other atoms in group 6A (16) obtain an octet by forming two covalent bonds….How Many Covalent Bonds Are Formed?

The tendency of an atom to attract electron or bonding pair of electrons i known as electronegativity. Halogens have high electronegativity. The electronegativity decreases as we move down group 17 because of the increase in nuclear radii. In group 17, fluorine is the most electronegative element.

astatine

The period 5 transition metals are yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), and cadmium (Cd).

T is the smallest non-metal other than noble gases.

Trends in Atomic Radius of Group 2 Elements

Going down group 2: there are more filled shells between the nucleus and the outer electrons … so the electrons in the higher energy levels are further from the nucleus … the atomic radius increases.

Uses of Group 2 Compounds

• Be is used in the manufacture of alloys. Cu-Be alloys are used in the preparation of high strength springs.
• Mg is used to prepare alloys with Al, Zn, Mn and Sn. Mg-Al alloys are used in construction of aircrafts.
• Ca is used in the extraction of metals from their oxide.
• Radium salt are used in radiotherapy.

Included in the group two elements are Beryllium(Be), Magnesium(Mg), Calcium(Ca), Strontium(Sr), and Barium(Ba). Usually, there is no need to store these elements in oil, unlike the group one elements. For a metal, alkali earth metals tend to have low melting points and low densities.

Answer. The property that is common to all group 2 elements is that they tend to form ionic bonds by losing electrons making these atoms positive charge. These elements are beryllium, magnesium, calcium, strontium, and radium.

Group 2 Elements are called Alkali Earth Metals. Generally the melting point of the metals decreases down the group. This is because as the metal ions get larger the distance between the bonding electrons and the positive nucleus gets larger and reduces the overall attraction between the two.

2)If mass is decreasing and volume is increasing simultaneously, then the density (mass/volume) will decrease. Generally, we see that in alkali metals the rate of increase of mass is greater than rate of increase of volume, therefore the density increases down the group.