When this element was discovered, it exhibited luster and malleability, and it reacted very vigorously with water. This element
is never found as a free element in nature and always exists in a compound. To which group does this element most likely belong? a) alkali metals
b) halogens
c) noble gases
d) transition metals
The element described above definitely belonged to the alkali metals, the first group on the periodic table. They show the properties indicated in the text.
They are metals because only metals are lustrous and malleable. This eliminates the possibility of them being halogens and noble gases.
Only group 1 metals reacts vigorously with water to form alkali.
Alkali are aqueous solutions that are basic in nature.
The reactivity of group 1 metals is due to their one extra electrons in the outer most shell.
These electrons are easily and readily lost in order for such atoms to gain stability and replicate the nearest noble gases.
The most reactive metal belongs to this group elements.
This is why it is nearly impossible to find them occurring alone in free state.
Some of the elements in this group are Li, Na, K, Rb, Cs and Fr.
Transition metals have variable oxidation states and some can be found alone in nature.
Answer is: both reactions
are exothermic. <span>
In exothermic reactions, heat is released and enthalpy of reaction is less than
zero (as it show second chemical reaction).
According to Le Chatelier's principle when the reaction
is exothermic heat is included as a product (as it show first
chemical reaction).</span>
One type of chemical process that can be either exothermic or endothermic is dissolving of salts in water. A salt is a compound made up of positively charged ions and negatively charged ions which are held together in a solid state because the positive and negative charges attract one another.
