Something with a density greater than 1.00 g ml will sink in waterThe density of water is 1 gm/cm^3=1000 kg/m^3, therefore, any element or object with density greater than 1 will sink in water.
Examples of elements with density greater than 1:
Aluminum (2700 kg/m^3 = 2.7 gm/cm^3)
Nickel ( 8910 kg/m^3 = 8.91 gm/cm^3)