Chemistry
An atom of an element has two electrons in the M shell. What is the
(a) atomic number
(b) number of protons in this element?
Related Questions
Define the terms :
(a) mass number
(b) ion
(c) cation
(d) anion
(e) element
(f) orbit.
From the symbol 42He for the element helium, write down the mass number and the atomic number of the element.
Five atoms are labelled A to E.
Atoms Mass no. Atomic no. A 40 20 B 19 9 C 7 3 D 16 8 E 14 7 (a) Which one of these atoms:
(i) contains 7 protons
(ii) has electronic configuration 2, 7?
(b) Write down the formula of the compound formed between C and D.
(c) Predict :
(i) metals
(ii) non-metals.