Helium, lithium, and sodium are all in the same color category on the periodic table because they are grouped together based on their similar properties. Typically, periodic tables use colors to represent different categories of elements, such as metals, non-metals, and noble gases.
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Helium (He) is a noble gas, which are typically color-coded in a specific way, often distinct from the metals.
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Lithium (Li) is an alkali metal, and sodium (Na) is also an alkali metal. These metals might be shown in the same color category because they both belong to Group 1 of the periodic table, known for having similar chemical properties, such as being highly reactive and having one electron in their outer shell.
If the periodic table you are referencing has these elements in the same color, it's likely because they are grouped under a specific category for clarity, even though they are fundamentally different types of elements (noble gas vs. alkali metals). Always check the color legend on the specific periodic table for precise classification.