Silicon has three stable isotopes. The most common form is ²⁸Si at 92.2% natural abundance with a mass of 27.9769 amu, ²⁹Si has a 4.7% natural abundance, while ³⁰Si has a natural abundance of 3.1% and a mass of 29.9738 amu. Calculate the mass of the ²⁹Si isotope.

What is the symbol for the halogen element in Period 4?

The typical amounts of essential elements in an adult weighing 60 kg are 2 - 39 kg for major elements, 36 - 1000 g for macrominerals, and 2 - 3600 mg for microminerals. Which of the following is the identity of the essential element that is around 120 g in a 60 kg adult?

Match the element with the family name 

            _____ sodium                        A.  Halogen

            _____ chlorine                       B.  Transition metal

            _____  iron                             C.  Alkali metal

            _____ xenon                          D.  Noble gas

Identify which classification each element belongs to: 

A. Alkali Metal     

B. Alkaline Earth Metal     

C. Pnictogen     

D. Chalcogen     

E. Halogen     

F. Noble Gas     

G. Transition Metal     

H. Inner Transition Metal     

I. Representative Element     

J. Lanthanide     

K. Actinide

1) Mg

2) H

3) Cl

4) No

5) P

6) Fe

Classify the following elements as atomic or molecular.

a. argon

b. chlorine

c. sodium

d. oxygen

Which statement below describes a solid.

A sample of NaCl was decomposed into 4.26 g of sodium and 6.57 g of chlorine. 

If another sample was to undergo the same process, which of the following values would be consistent with the law of definite proportions?

Choose the statement that is NOT part of Dalton's Atomic Theory

A. Atoms are regrouped through a chemical reaction.

B. Compounds formed are in whole-number ratios of different atoms of elements.

C.  Atoms, the basic particles of matter, cannot be created or destroyed.

D. Protons, neutrons, and electrons are subatomic particles that comprise the atom. 

E. A particular element has chemically and physically identical atoms.

How did Rutherford's gold-foil experiment contribute to the development of the atomic model?

Classify if the statement is true or false. If it is false, correct the statement.

There is a decrease in the frequency of radiation as its wavelength decrease.

The UV (ultraviolet light) lies on the left of the electromagnetic spectrum. While infrared (IR) lies on the right. Which statement is true?

(1) the wavelength of IR light is lower than UV light

(2) the frequency of IR light is lower than UV light

(3) the energy of IR light is lower than UV light

(4) the energy of IR light and UV light are the same

Based on the Bohr model for the hydrogen atom, the emitted light with the longest wavelength is the transition

Which of the following statement is correct?

a. The shape of the orbital is determined by the quantum number ml.

b. The spin of the electron of an orbital is determined by the quantum number ms. 

c. The orientation in space of the orbital is determined by the quantum number l.  

d. The size of the orbital is determined by the principal quantum number n.

What is the numerical value of n corresponding to 4p?

Determine the number of subshells in the following: first shell, second shell, and third shell.

Which is a negatively charged particle in an atom as a pair of opposite spins?

How many orbitals are present in the second shell? What about the third shell?

What is the complete electron configuration of polonium (Po)?

Determine the group number of bromine. Provide the number of electrons each of its shells holds and the electron configuration in its valence shell.

What is the condensed electron configurations for indium (In) atom?