Which of the following statements about sodium metal is INCORRECT according to basic chemistry of reactive metals?

Introduction / Context:
This question checks your understanding of the properties of sodium, a highly reactive alkali metal. Group 1 metals have characteristic reactions with air and water and are handled with care in laboratories. You are asked to identify which statement about sodium is incorrect, so you need to recall its classification in the periodic table and its typical reactions.

Given Data / Assumptions:

• Sodium is an element in the periodic table, symbol Na.
• Options describe its reactivity with oxygen and water, storage method and its classification as metal or non metal.
• We assume standard school level knowledge of alkali metals.

Concept / Approach:
Sodium is an alkali metal in group 1 of the periodic table. It is soft, silvery and highly reactive. It reacts vigorously with water to produce sodium hydroxide and hydrogen gas, releasing heat. It also reacts with oxygen in air to form oxides or peroxides. Because of its reactivity, sodium is stored under kerosene to keep it away from air and moisture. Therefore, any statement claiming that sodium is a non metal is incorrect, since it is clearly a metal by both physical and chemical properties.

Step-by-Step Solution:
Step 1: Recall that sodium belongs to group 1 (alkali metals) and is therefore a metal. Step 2: Think about the reaction of sodium with water: 2Na + 2H2O → 2NaOH + H2. This reaction is vigorous and exothermic, confirming that sodium reacts strongly with water and generates significant heat. Step 3: Sodium also reacts readily with oxygen in air to form sodium oxide or sodium peroxide, again showing high reactivity. Step 4: Because it reacts with air and moisture, sodium metal is stored in kerosene or mineral oil to protect it from accidental reaction, so the statement about storage in kerosene is correct. Step 5: Sodium oxide is a basic oxide, which supports the statement that sodium forms basic oxides. Step 6: The only statement that contradicts basic facts is the claim that sodium is a non metal. Step 7: Therefore, the incorrect statement is It is a non-metal.

Verification / Alternative check:
You can verify sodium's metallic nature by physical properties: it has metallic lustre, conducts electricity and is malleable and ductile, although soft. In the periodic table, it clearly appears among metallic elements. Chemistry texts classify sodium as a typical metal that forms ionic compounds such as sodium chloride and sodium hydroxide. This overwhelming evidence confirms that describing sodium as a non metal is wrong.

Why Other Options Are Wrong:
In this question, wrong options mean statements that are actually correct and therefore cannot be chosen as incorrect. Sodium does react vigorously with oxygen and water, producing a lot of heat. It is indeed stored in kerosene, a standard safety precaution. It forms basic oxides, such as sodium oxide, which react with water to give a strong base. These statements are consistent with the known behaviour of sodium and are not incorrect descriptions.

Common Pitfalls:
One possible source of confusion is mixing up the properties of sodium with those of non metals such as phosphorus or sulphur, which have very different behaviour. Another pitfall is to misread the question and forget that it is asking for the incorrect statement instead of the correct one. Always pay attention to words like correct, incorrect, true, false or not in such questions, since they reverse what you need to select.

Final Answer:
The incorrect statement about sodium is that it is a non-metal.