Atomic Structure
Which subatomic particle has a positive charge?
Proton
Atoms of the same element with different numbers of neutrons are called what?
Isotopes
How many electrons can the first energy level hold?
2 electrons
Horizontal rows on the periodic table are called what?
Periods
Across a period from left to right, atomic size generally changes in what way?
It decreases
Which particle determines the identity of an element?
Proton
A neutral oxygen atom has 8 protons. How many electrons does it have?
8 electrons
How many valence electrons does fluorine have?
7 valence electrons
Vertical columns on the periodic table are called what?
Groups or families
In its neutral state, which atom is larger: sodium or chlorine?
An atom has 9 protons and 10 electrons. What is its overall charge?
1-
How many neutrons are in chlorine-37 if chlorine has atomic number 17?
20 neutrons
Give the Bohr electron arrangement for magnesium, atomic number 12.
2-8-2
Which group contains elements with full outer energy levels?
Group 18, the noble gases.
Which has higher electronegativity: magnesium or chlorine?
Chlorine
An atom contains 11 protons, 12 neutrons, and 11 electrons. What is its mass number?
23
What happens to an atom when it loses two electrons?
It becomes a 2+ ion
Which element from H through Ar has the electron arrangement 2–8–7?
Chlorine
Which two elements are in Group 1 and Periods 2 and 3?
Lithium and sodium
Why are noble gases usually unreactive?
Their outer energy level is full
Most of an atom is empty space. Where is almost all of its mass located?
The nucleus
Two atoms each have 6 protons. One has 6 neutrons and the other has 8. Explain their relationship.
They are carbon isotopes with different mass numbers
An unknown atom has three occupied energy levels and one valence electron. Identify the element from H through Ar.
Sodium
An element lies in Period 3, Group 16. Identify it and state its number of valence electrons.
Sulfur, 6 valence electrons
Compare sodium and fluorine. Predict which loses an electron and which gains one during a reaction.
Sodium loses one electron; fluorine gains one electron