Question

sodium has low density but it is a metal explain the statement​

Answer 1

An element is called a metal based on its electronic configuration. All elements except hydrogen that have 3 or less electrons in their outermost shell are classified as metals. Going by this definition, sodium whose outermost shell has 1 electron, is a metal.

It has low density because it has a comparatively large volume. In the modern periodic table the size generally decreases as we move to the right of a period while the mass increases. Hence density increases along a period. This means the elements in the first group (column), which includes some of the most metallic elements like sodium, potassium, rubedium and caesium have low density.