Question

unit 2 study guide
topics covered:
atomic history: atomic models
atomic structure: protons, neutrons, electrons
periodic trends: atomic radius, electronegativity, ionization, etc.
isotopes: isotope notation, definitions, finding particles
ions: gaining/losing electrons, cations, anions, finding electrons from the symbol
average atomic mass: calculating mass using percent abundance
configurations: orbitals, electron configuration, noble gas configurations

mass charge location
protons
neutrons
electrons

name symbol mass # atomic # protons neutrons electrons
boron b 11 5
sodium -26 11
y 89 39
copper - 58 29
tc 98 43
pb 207
thallium 81
h 0

sketch the periodic table in the space below and then draw arrows to show the periodic trends.

Explanation:

Step1: Recall atomic - particle properties

Protons have a mass of approximately 1 amu, a positive charge of + 1, and are located in the nucleus.
Neutrons have a mass of approximately 1 amu, no charge (charge = 0), and are located in the nucleus.
Electrons have a very small mass (about $\frac{1}{1836}$ amu), a negative charge of - 1, and are located outside the nucleus in electron - orbitals.

Step2: Use atomic number and mass number relationships

For an atom, the atomic number (Z) is equal to the number of protons. The mass number (A) is the sum of protons and neutrons ($A = p + n$), and in a neutral atom, the number of electrons is equal to the number of protons.

• Boron: Atomic number = 5, so number of protons = 5. Mass number = 11, number of neutrons = $11 - 5=6$. In a neutral atom, number of electrons = 5.
• Sodium - 26: Atomic number of sodium is 11, so number of protons = 11. Mass number = 26, number of neutrons = $26 - 11 = 15$. In a neutral atom, number of electrons = 11.
• Yttrium (Y): Atomic number = 39 (since number of electrons = 39 in a neutral atom). Mass number = 89, number of neutrons = $89 - 39=50$.
• Copper - 58: Atomic number of copper is 29, so number of protons = 29. Mass number = 58, number of neutrons = $58 - 29 = 29$. In a neutral atom, number of electrons = 29.
• Technetium (Tc): Atomic number = 43, so number of protons = 43. Mass number = 98, number of neutrons = $98 - 43=55$. In a neutral atom, number of electrons = 43.
• Lead (Pb): Atomic number of lead is 82. Mass number = 207, number of neutrons = $207 - 82 = 125$. In a neutral atom, number of electrons = 82.
• Thallium: Atomic number = 81, so number of protons = 81. For a neutral atom, number of electrons = 81. Let's assume a common isotope with mass number 204, number of neutrons = $204 - 81=123$.
• Hydrogen (H): If number of neutrons = 0, and assuming a common isotope (protium), atomic number = 1, so number of protons = 1. In a neutral atom, number of electrons = 1.

Answer:

	Mass	Charge	Location
Neutrons	1 amu	0	Nucleus
Electrons	$\frac{1}{1836}$ amu	- 1	Outside nucleus

Name	Symbol	Mass #	Atomic #	Protons	Neutrons	Electrons
Sodium - 26		26	11	11	15	11
Yttrium	Y	89	39	39	50	39
Copper - 58		58	29	29	29	29
Technetium	Tc	98	43	43	55	43
Lead	Pb	207	82	82	125	82
Thallium		204 (assumed)	81	81	123	81
Hydrogen	H	1	1	1	0	1