<u>Explanation:</u>
<u>For 1:</u> Lithium
This element belongs to Group 1 and is considered as a metal. This metal is soft, shiny and shows a property of malleability.
Thus, the correct answer is Malleable, soft and shiny.
<u>For 2:</u> Lead
This element belongs to Group Group 14 and is a solid substance. This element has higher density and is opaque in nature.
Thus, the correct answer is Opaque solid with higher density.
<u>For 3:</u> Fluorine
This element belongs to Group 17 and is a gas. This is highly reactive gas because this element requires only one electron to attain stability and also due to its small size. This is very reactive.
Hence, the correct answer is highly reactive gas.
<u>For 4:</u> Krypton
This element belongs to Group 18 and is considered as a noble gas. Noble gases are the stable gases ans are non-reactive in nature.
Thus, the correct answer is Nonreactive gas.