Atomic Theory & Periodic Table

A neutral atom contains 12 neutrons and 11 electrons. What is the number of protons in this atom?

11

If an atom of Chlorine has a charge of -1, how many protons, neutrons, and electrons does it have?

17 protons, 18 neutrons, 18 electrons

If a Calcium ion has a charge of +2, how many protons, neutrons, and electrons does it have?

20 protons, 20 neutrons, and 18 electrons

An atom has 19 protons and 20 neutrons. Calculate its mass number.

39

The atomic number of oxygen is 8. Therefore, which of the following answers would correspond to what would be in the nucleus of an oxygen atom?

8 protons and 8 neutrons

Thallium has two isotopes, thallium-203 and thallium-205. Thallium's atomic number is 81 and its atomic mass is 204.38 amu. Which statement about the thallium isotopes is true?

Atoms of both isotopes have 81 protons.

Which of the elements below have seven electrons in their outermost energy levels?

Br, I, and Cl

Using your periodic table, which element below has the smallest atomic radius? Sodium Iron Phosphorus Chlorine

Chlorine

Which of the following Halogens is the most reactive? Chlorine Bromine Iodine Fluorine

Fluorine

A chlorine atom becomes stable by having 8 valence electrons by __________.

Gaining one electron

Using your periodic table, determine which element below is malleable and ductile? Gallium Fluorine Phosphorus Silicon

Gallium

Sodium, mercury, argon, and neon are used in the production of lamps. There are fewer safety guidelines regarding the handling of neon and argon than for mercury and sodium. Which of the following best describes the elements within the group of the periodic table that contains neon and argon gas?

Gaseous at room temperature and mostly unrecative with metals.

Using your periodic table, check all of the elements below that are classified as nonmetals. Hydrogen(H) Mercury(Hg) Argon(Ar) Neon(Ne) Iron(Fe) Chlorine(Cl) Cobalt(Co)

Hydrogen(H) Argon(Ar) Neon(Ne) Chlorine(Co)

Using your periodic table, check all of the elements below that are classified as metal. Iodine(I) Lead(Pb) Helium Manganese(Mn) Phosphorus(P) Potassium(K) Rubidium(Rb)

Lead(Pb) Manganese(Mn) Potassium(K) Rubidium(Rb)

Based on electron configurations, which of the following pairs of elements contains the same number of energy levels?

Lithium (Li) and Neon (Ne)

Using your periodic table, which of these elements are the best conductor of electricity? S N Br Ni

Ni

Which group of elements are characterized by stability and lack of reactivity?

Noble gases

How does a Sulfur^-2 ion differ from a neutral Sulfur atom?

Number of electrons

A forensic scientist is comparing two samples of evidence to see if they contain the same elements. Here are his findings: - Sample A contains atoms which all have a mass number of 40 and a atomic number of 20. -Sample B contains atoms which all have a mass number of 40 and an atomic number of 19. Which conclusion is valid?

One sample contains atoms of Calcium and the other sample contains atoms of Potassium.

The nucleus of an atom is made up of what subatomic particles?

Protons and neutrons

Where on the periodic table are the MOST reactive metals found?

The lower left

What is the identity of an element determined by?

The number of protons

Which feature of the electron configuration determine the chemical properties of an element?

The number of valence electrons.

Which of the following qualities is NOT typical of metals?

They form negative ions.

Why do noble gases almost never form chemical bonds with other atoms and so can be found in nature?

They have filled outer valence shells.

Group 17 elements, the Halogens, are the most reactive nonmetals because why?

They require only one electron to fill their outer energy level.