Which f the following statement is always correct?

The ion of an element has 3 positive charges. The mass number of atom of this element is 27 and the number of neutrons is 14. What is the number of electrons in the ion?

The first model of an atom was given by:

From the symbol <ιμγωιδτη=∀31∀ηειγητ=∀32∀σρχ=∀Χη−4_Στρυχτυρε−οφ−Ατομ−1_φιλεσ/ιμαγε009.πνγ∀>, state:

(i) mass number of phosphorus,

(ii) atomic number of phosphorus, and

(iii) electron configuration of phosphorus.

The atom of an element X has 7 electrons in its M shell

(a) Write the electronic configuration of element X.

(b) What is the atomic number of element X?

(c) Is it a metal or a non-metal?

(d) What type of ion will be formed by an atom of element X? Write the symbol of the ion formed.

(e) What could element X be?