Thinking Critically Compare the e/m ratio value you obtained with the accepted value of in Software

Encoder QR in Software Thinking Critically Compare the e/m ratio value you obtained with the accepted value of

cathode ray Cathode ray tubes, or CRT for short, are used extensively in video monitors and televisions The electrons are ejected from the electron gun and directed at a screen coated with substances that glow different colors when struck with the electrons The electron beam must strike different regions of the screen at different times and frequencies to create a clear

image With the experience gained in this lab, what force do you think is used to deflect the beam of electrons 2 The electron gun used in a CRT is located centered behind the screen The beam is precisely deflected to reach specific spots on the screen Why are large-screen CRT displays longer (deeper) than small-screen CRT displays

he periodic table organizes a remarkable amount of information about the chemical and physical properties of the elements The information is organized in such a manner that trends in properties and important relationships can be readily identified In this activity, you will identify several elements based on their properties and the properties of the surrounding elements in the periodic table

Construct a simplified version of the periodic table Identify trends and relationships among elements in the same group Identify trends and relationships among elements in the same period Draw conclusions about the predictability of chemical properties of the elements

1 For each unknown element listed in Data Table 1,

number uniquely identifies a chemical element Explain how the property uniquely identifies each atom 2 Describe the general characteristics of metals, nonmetals, and metalloids 3 Read over the entire laboratory activity Develop a hypothesis about which properties are the most useful for identifying the group to which an unknown element belongs Develop a hypothesis about which properties are the most useful for determining the sequence of the elements within a group Develop a hypothesis about which properties are the most useful for identifying the period to which an element belongs Record all of your hypotheses on page 43

3 4 5

copy its chemical and physical properties onto separate index cards Be sure to record the letter of the unknown element on each index card The following abbreviations are used in Data Table 1: IP ionization potential, BP boiling point, MP melting point Begin by grouping cards that have common chemical properties You should have eight groups Within each group of cards, arrange the cards into a column based on their physical properties Arrange the groups from left to right, based on trends in physical and chemical properties Based on the arrangement of the cards from step 4, record the letter of each index card in its corresponding location in Data Table 2

Physical properties colorless monatomic gas; density less than atmosphere; IP 246 eV; BP 272 C; MP 269 C colorless monatomic gas; density similar to that of the atmosphere; IP 216 eV; BP 249 C; MP 246 C colorless monatomic gas; density greater than that of the atmosphere; IP 158 eV; MP 189 C; BP 186 C IP 105 eV; MP 44 C; BP 280 C

forms many different oxides reacts with oxygen to form monoxides and dioxides, forms tetrahalides forms binary compounds with most metals and all semiconductors reacts violently with oxygen forms binary compounds with most metals and all semiconductors causes glowing splint to go out, forms many different oxides forms a monoxide when reacted with oxygen forms trihalides reacts with oxygen, forms a dihydrogen compound causes glowing splint to burst into flame, causes glowing steel wool to burst into flame, forms an orange compound when reacted with iron, forms a dihydrogen compound forms tetrahalides, forms dioxides burns brightly in presence of oxygen to form a white powder, reacts with acid to form hydrogen gas, forms a monoxide when burned with oxygen reacts quickly with the atmosphere, readily forms ions in water reacts quickly with the atmosphere, readily forms ions in water forms trihalides

conducts electricity and heat in its brittle, black, solid form; not conductive in its very hard, crystalline form; IP 113 eV; MP 3652 C pale yellow diatomic gas; IP BP 188 C 174 eV; MP 220 C;