Which element would have this representation: 43 ? 21 question 4 options: technetium scandium titanium cobalt

The naswer to your question is Scandium

Explanation:

43 means the atomic mass is normally presented as a power

21 means atomic number is always a subscript

                   ₂₁ ? ⁴³

Technetium             ₄₃Tc⁹⁸

Scandium                 ₂₁Sc⁴⁴      

Titanium                   ₂₁Ti⁴⁷

Cobalt                      ₂₇Co⁵⁹

B. Scandium is the answer

Explanation:

When we look at this Nuclide symbol we get to know that 21 is the atomic number as it is in the subscript and 43 is the mass as it is in the superscript.

We identify an element from its atomic number by looking at the periodic table.

Atomic number 21 is element Scandium. Sc-43 is one of the isotope mentioned here.

We don’t use mass number to identify an atom.

we can conclude that the melting point of table salt is above room temperature (it's actually 801 deg c). the melting point of mercury must be below room temperature (- 39 deg c).

> b takes place in the gas phase in an isothermal tubular reactor. the feed is one mole of a per one mole of c, an inert. the entering temperature and pressure are 427°c and 10 atm, respectively. the gas constant r = 0.08206 atm · l/mol · k.