Which of the following are properties of metalloids? A. Semi-conductors
B. All of these
C. React like metals sometimes
D. React like non-metals sometimes

Which of the following did jj thompson discover about atoms? a)an atom has an internal structure. b) atoms are tiny indivisible particles. c)electrons orbit the nucleus of an atom. d) the nucleus of an atom contains protons and neutrons.

How many moles is 14.5 cm^3 of platinum? the density of platinum is 21.45 g/cm^3.

What mass of natural gas (ch4) must you burn to emit 276 kj of heat?