The mass number plays an important role for elements and their isotopes. Mass number comes from the addition of protons and neutrons (their weight). Isotopes are the elements, but with a different number of neutrons. So in turn, by subtracting the number of protons (atomic number) from the mass, you can find the number of neutrons.
Answer:
Option (A) : Positive
Explanation:
A combustion reaction will always be associated with a change in entropy that is Positive due to the gaseous products released. Hence, there is a large positive entropy change.
Answer:
D. the sea of electrons
Explanation:
Metallic bonds are defined as the bonds formed between two or more metals. Silver atom form metallic bond with other silver atoms.
In metallic bond, the free electrons or valence electrons present in s and p orbitals delocalize. The valence electrons do not move around the atoms or enter the atoms whereas they form a sea of electrons in which they surround the nuclei (positively charged) of the metal ions interacting. The valence electrons are then freely move in the space between the atomic nuclei.
Hence, the correct answer is "D. the sea of electrons".
Answer:
Explanation:
A pinhole camera is a simple camera without a lens but with a tiny aperture, a pinhole camera – effectively a light-proof box with a small hole in one side. Light from a scene passes through the aperture and projects an inverted image on the opposite side of the box, which is known as the camera obscura effect.
