Answer:
D
Explanation:
A. Is wrong
Salt water is not an element. In fact it contains sodium and chlorine asides the elements of the water
B is wrong
It is a mixture but it is not heterogeneous. It is not heterogeneous in the sense that when you take a sample of salt, the composition is throughout the same I.e containing salt and water
C is incorrect
It is a mixture of salt and water. They are both compounds and hence they both exist together as a mixture
D is correct
It is correct because, a sample of salt water irrespective of the amount taken for observation would contain salt and water
Answer:
Chemically
Explanation:
Because chemical bonds form between the atoms.
Answer: BF3
Explanation: boron needs 4 electron to obtain octet and Fluorine has just one. For the valence shell to be completely filled it will have to form BF4- with 4 fluorine atom surrounding it.
Dalton's theory explained that all matter constitutes of atoms that are indivisible and indestructible. They combine in definite ratios and posses definite masses. He considered atom to be the smallest particles that the matter is composed of. He basically explained about the chemical properties of matter.
After many more researches, it was explained that atom is not the smallest particle that the matter is composed of but it contains many subatomic particles like protons, neutrons and electrons that the matter is made of. Dalton could not explain about the nuclear property of atom.
