form where a river ends and becomes a body of water such as a lake or an ocean

       Deltas          form where a river ends and becomes a body of water such as a lake or an ocean

Explanation:

Rivers flow continually from high points (in the mountains) until they reach a broad, extensive body of water at low levels (normally 0 meters altitude), like a lake or an ocean ,where they empty their water and sediments.

The landform created is named delta.

Deltas are regions flooded with many streams of water that find their way to the lake or ocean.

Some examples of deltas are The Mississippi Delta and the Nile Delta.

You can see attached a picture of a delta taken from the internet.

"among the transition metal elements, manganese and zinc have a slight lowering of electronegativities. the reason behind this is that the nuclear charges of these elements are slightly weaker than the other transition metal elements due to the way their valence electrons are filled up. both manganese and zinc have their valence electrons filled up to the 4th shell with 1 pair of electrons (4s2) completely occupying it. although the electrons in the 3rd shell (3d) are yet to be paired since the outer most shell is filled up, the ability of the nucleus to attract electrons is lessened. hence,   the electronegativity (or the ability to attract electrons) is lessened."