You have to read the passage and compare and contrast the story
The nucleus, that dense central core of the atom, contains both protons and neutrons. Electrons are outside the nucleus in energy levels. Protons have a positive charge,neutrons have no charge, and electrons have a negative charge. A neutral atom contains equal numbers of protons and electrons.
First is homogeneous and so is the third. second is heterogeneous
Answer:
Law of definite proportions, statement that every chemical compound contains fixed and constant proportions (by mass) of its constituent elements.
Answer:
there r 118 elements in periodic table..
hope it helps.