University:
Thomas Jefferson University
Course:
CHEM 103 | Chemistry I
Academic year:

2024
Views:

15

Pages:

1
Author:

Imani H.

1/18/24 Silver-Ag lead-Pb 2) 3n- tin Xe-Xenon 3) 217MM/SM/μη 2176xx 6030 = 130 m Luin 1000 м Min Sec 4) 2.200.0149=0.01490 181.2 0-0149 Chapter 2 - Atoms, Molecules, & lons Elevents Composed of building blocks called atoms. Anton is formed when atous gain or loses Compounds are found when atoms combine to forme Molecules, elections. Ex' Examples of Isotopes Hydrogen has 3 isotopes HH SH ~99%-1% Radioachue Corbon has 3 isotopes (carbon dating) ~99%~1% Radiaactive For a neutral atom, the muber of elections Is equal to the rearber of protons. Conclusions →ball of positive charge Negative electrons 1) Most of the atom is expiy 2) Most of Mass is concentrated in a small volume called the nucleus (+) charge. 2.3 Atomic Struckre & Symbolism Election negative, very small Proba positive, Much larger than election Neutron neutral, Slightly larger than proton Albric mauber the number of protons in the artou. Cations are positive (loses elections) anions are negative (gain elections) The charge is indicated as a superscript to the right of the atomic Symbol. # of elections (# of protons)-(charge) Hass nuuber the total number of protons plos Neutrons written as a superscript to the left of the element symbol Ex Mass 24 2+ atomic Mg 12 charge # Br protons-35 nections-36 Ca 2+ protons 20 neutrons-18 a mass of 12 amu The atomic mass unit (amu) is based on the pure isotope 2C. 12C has exactly The atomic mass listed on the periodic table is a weighted average all over isotopes of that element. → depends on the relative abundance of all isotopes The frackmal abundance is the fraction of atoms that Occur naturally as a specific isotope. Average mass fim, FEM Mi Mare Masses of rotapes 1.2 fi, f₂ are frachanal abundances NOWI Oxygen has 3 primary iscloses "Ο (99.7571. 15.995 ανω), 170 (0.038.16.999) (0.205.17.9990w) Calculate the average мазз (0.99767) (15.995)+ 10.00038) (16.999) (0.00205) (17.999)=15.999 How to cakulate Dercent abundance Copper has 2 isotopes, 63 Cu & 65 Cu, with Masses 62.9296 $64.9278 ame. What is the percent abundance for each Isotope? ang. Mass 63.55 (from penodic table) let = fraction of 630 1-x= fraction of 68CU 63.55 x (62.9296) + (1-x) (64.9278). 63.6562.9296x64.9278-64.9278 63.55-64.9278 x= -1.38/-1.9852 0 713 0.713 x 100 = 71.3% Isotopes of an element have the same waber of protons but different number of Nations. 63 CO. 713% SC 28.71

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