Periodic Table
What does the atomic number tell you about an element?
The number of protons
Are groups horizontal or vertical?
Vertical.
Which category of element usually conducts heat and electricity well?
Metals.
Is color a physical or chemical property?
Physical property.
What is the formula for density?
Density = mass ÷ volume.
What are the horizontal rows of the periodic table called?
Periods
Which group contains the noble gases?
Group 18.
Most nonmetals are found on which side of the periodic table?
The right side.
Is flammability a physical or chemical property?
Chemical property.
Which element would most likely have the lowest density?
A. Platinum (Pt)
B. Copper (Cu)
C. Helium (He)
D. Iron (Fe)
C. Helium (He)
Why: Helium is a gas and has a much lower density than the listed metals.
Question:
An element box shows:
17
Cl
Chlorine
35.45
What do 17, Cl, and 35.45 represent?
17 = atomic number
Cl = chemical symbol
35.45 = average atomic mass
Why are noble gases generally very unreactive?
They have a full outer energy level.
Silicon has properties of both metals and nonmetals. What type of element is silicon?
Metalloid.
Sugar dissolves in water. Which physical property is being observed?
Solubility.
A rock has a mass of 40 g and a volume of 10 cm³. What is its density?
4 g/cm³
An element box shows:
30
Zn
Zinc
65.38
Identify the atomic number, symbol, and atomic mass.
Atomic number = 30; symbol = Zn; atomic mass = 65.38 amu.
Which element would most likely react similarly to oxygen: nitrogen, sulfur, fluorine, or neon?
Sulfur, because sulfur and oxygen are in the same group.
An unknown element is dull, brittle, and does not conduct electricity well. Is it more likely a metal, nonmetal, or metalloid?
Nonmetal.
A material bubbles and releases gas when placed in acid. What property is being demonstrated?
Chemical reactivity.
Liquid A has a density of 0.80 g/cm³ and Liquid B has a density of 1.40 g/cm³. An object has a density of 1.10 g/cm³. Where will it settle?
Between Liquid A and Liquid B.
An unknown element is located in Group 14, Period 6. Which element is it?
A. Carbon (C)
B. Silicon (Si)
C. Tin (Sn)
D. Lead (Pb)
D. Lead (Pb)
A student says potassium should react most similarly to calcium because the two elements are next to each other in the same period. Explain the student's mistake.
Elements in the same group, not necessarily the same period, tend to have similar chemical properties. Potassium would behave more similarly to another Group 1 element.
Scientists need a material that conducts electricity under certain conditions but not as well as a typical metal. Which type of element would be most useful, and why?
A metalloid because many metalloids act as semiconductors.
A scientist records that a substance is shiny, melts at 150°C, has a density of 2.7 g/cm³, and reacts strongly with acid. Identify the three physical properties and the one chemical property.
Physical: shiny appearance, melting point, density.
Chemical: reactivity with acid.
A scientist tests four unknown liquids:
Liquid: Density: Boiling Point
A 0.84 g/cm³ 82°C
B 1.02 g/cm³ 100 °C
C 0.84 g/cm³ 82°C
D 1.16 g/cm³ 95 °C
Which two liquids are most likely the same substance, and what evidence supports your answer?
Liquids A and C.
They have the same density and the same boiling point, which provides evidence that they may be the same pure substance.