Atomic structure

9-Number of neutrons is equal to mass no. - atomic no.

19-The electron configuration of potassium is ..............

4. Atoms of the same element must always have the same number of _________

13-The period no. = the no. of shells

17-The nucleus is positively charged because it has...

6-The dense, positively charged mass located in the center of the atom.

12-Locate the position of 20Ca in the modern periodic table Mg ( 2, 8,8, 2 )

16-The atom is neutral (uncharged) in ordinary state because .........................

18-..................Shows an element's chemical symbol, atomic number, atomic mass and symbol for state of matter at room

5. What is the mass number of aluminum  (Al)?

10-Where are electrons found in an atom?

7-The _________ equals the number of protons in an atom of that element

3- How many neutrons are in an atom of sodium (Na)? (Remember : Neutrons no. = Mass no. - Atomic no. )

15-What is the electron configuration of nitrogen ..........

11-The chemical symbol of magnesium is ....................

8-The __________ is the sum of the protons and neutrons in the nucleus of that atom.

1. All elements are composed of.................

14-The group no. = the no. of electrons in outer shells ( valence electrons )

2. How many electrons are in an atom of carbon (C)? (Remember : Atomic Number = no. of Protons or no. of Electrons)