<span>All metals have similar properties BUT, there can be wide variations in melting point, boiling point, density, electrical conductivity and physical strength.<span>To explain the physical properties of metals like iron or sodium we need a more sophisticated picture than a simple particle model of atoms all lined up in close packed rows and layers, though this picture is correctly described as another example of a giant lattice held together by metallic bonding.</span><span>A giant metallic lattice – the <span>crystal lattice of metals consists of ions (NOT atoms) </span>surrounded by a 'sea of electrons' that form the giant lattice (2D diagram above right).</span><span>The outer electrons (–) from the original metal atoms are free to move around between the positive metal ions formed (+).</span><span>These 'free' or 'delocalised' electrons from the outer shell of the metal atoms are the 'electronic glue' holding the particles together.</span><span>There is a strong electrical force of attraction between these <span>free electrons </span>(mobile electrons or 'sea' of delocalised electrons)<span> (–)</span> and the 'immobile' positive metal ions (+) that form the giant lattice and this is the metallic bond. The attractive force acts in all directions.</span><span>Metallic bonding is not directional like covalent bonding, it is like ionic bonding in the sense that the force of attraction between the positive metal ions and the mobile electrons acts in every direction about the fixed (immobile) metal ions of the metal crystal lattice, but in ionic lattices none of the ions are mobile. a big difference between a metal bond and an ionic bond.</span><span>Metals can become weakened when repeatedly stressed and strained.<span><span>This can lead to faults developing in the metal structure called 'metal fatigue' or 'stress fractures'.</span><span>If the metal fatigue is significant it can lead to the collapse of a metal structure.</span></span></span></span>
Complete question is;
Chemical reactivity of alkali metals increases down the group while reactivity of halogens decreases down the group. Give reasons
Answer:
Explained below
Explanation:
Alkali metals exhibit reactivity due to their electropositivity. Now, for alkalis, their electro-positivity increases down their group. Since their reactivity increases with increase in electropositivity, it means their reactivity also increases down the group.
Whereas, the reactivity of halogens occurs as a result of their electronegativity. Now, electronegativity for halogens decreases down the group. Since their reactivity decreases with decrease in electronegativity, it means that their reactivity will also decrease down the group.
Mass, if you know what element you are working with.
It provides us with the knowledge of what the cation and anion of the compound are, as well as how many atoms of each are present.
13 - Periodic table
14 - Dimitri mandeleev
15 - groups
Mark me brainiest pls it right answer
