Answer:
B) sand
Explanation:
A) Oil is a wrong choice because it is a liquid not a solid and also if it is oil, it will float over the water surface as a droplets.
B) Sand is the right choice, because sand is a solid and it does not dissolve in water and stabilizes at the bottom.
C) Sugar is a wrong choice, because small amount of sugar will dissolve in water and be a homogeneous solution and does not appear as a particles.
D) Wood ships is also a wrong choice, even it is a solid and does not dissolve in water, but it will float over the water surface.
Answer:

Explanation:
A covalent bond involves the sharing of electrons to make the atoms more stable, and so they satisfy the Octet Rule (8 valence electrons).
Typically each atom contributes an electron to form an electron pair. This is a single bond. There are also double bonds (two pairs of electrons), triple bonds (three pairs of electrons), and coordinate covalent bonds.
Sometimes, to satisfy the Octet Rule and achieve stability, one atom contributes both of the electrons in an electron pair. This is different from other covalent bonds because usually each of the 2 atoms contributes an electron to make a pair.
Answer:
A piece of gold foil was hit with alpha particles, which have a positive charge. Most alpha particles went right through. This showed that the gold atoms were mostly empty space. Some particles had their paths bent at large angles. A few even bounced backward. The only way this would happen was if the atom had a small, heavy region of positive charge inside it.