Thus nanoparticles have a much ____________ surface area per unit mass compared with larger particles.
Thus nanoparticles have a much ____________ surface area per unit mass compared with larger particles.
The correct option is A Greater
Two principal factors cause the properties of
nanomaterials to differ significantly from other materials: increased relative
surface area, and quantum effects. These factors can change or enhance
properties such as reactivity, strength and electrical characteristics.
As a particle decreases in size, a greater
proportion of atoms are found at the surface compared to those inside. For example,
a particle of size 30 nm has 5% of its atoms on its surface, at 10 nm 20% of
its atoms, and at 3 nm 50% of its atoms.
Thus nanoparticles have a much greater surface
area per unit mass compared with larger particles. As growth and catalytic
chemical reactions occur at surfaces, this means that a given mass of material
in nanoparticulate form will be much more reactive than the same mass of
material made up of larger particles.
Two principal factors cause the properties of nanomaterials to differ significantly from other materials: increased relative surface area, and quantum effects. These factors can change or enhance properties such as reactivity, strength and electrical characteristics.
As a particle decreases in size, a greater proportion of atoms are found at the surface compared to those inside. For example, a particle of size 30 nm has 5% of its atoms on its surface, at 10 nm 20% of its atoms, and at 3 nm 50% of its atoms.
Thus nanoparticles have a much greater surface area per unit mass compared with larger particles. As growth and catalytic chemical reactions occur at surfaces, this means that a given mass of material in nanoparticulate form will be much more reactive than the same mass of material made up of larger particles.
