The literary device being described is a simile, a figure of speech that compares two different things using "like" or "as". In this case, it compares something unwieldy, slow, heavy, and pale as lead.
Lead is heavy.
The simile "as heavy as lead" means something is extremely heavy or burdensome. Lead is a dense and weighty material, so when an object or situation is compared to lead, it conveys a sense of great heaviness.
Yes
Heavy metals as lead retain nuclear radiations.
It is almost twice as heavy as lead.
Yes.
lead is soft and malleable heavy and post-transition metal
Lead
1 pound.
lead
No. Heavy metals include things like Lead (Pb)
Heavy, soft, and inexpensive. Gold is also heavy and soft, but is too expensive to use.