what element is Zr?
Zirconium
Why do elements within a group have similar chemical properties?
They have a similar configuration of outer-shell electrons.
What is the symbol for element Roentgenium?
Rg
What type of microscope uses electrons to provide a three-dimensional view of the surface of the object?
Scanning electron microscope
Beth accidentally left her crayon box in the car on a hot day. What happened to her crayons?
Crayons melted; changed from solid to liquid
These pictures show different models of the atom proposed by scientists. The proper arrangement from oldest to most recent would be __________.
TRQS
Why was Democritus’s original atomic theory revised?
Claimed atoms could not be divided
K+
Aluminum is used for making cooking utensils. Which of the following properties of Aluminum are responsible for the same? I. Good thermal conductivity II. Good electrical conductivity III. Ductility IV. High melting point
I and IV
Alfie is wearing a pair of glasses and enters a warm house after being outside on a cold day. His glasses fog up because of _____________.
Condensation
Why is the human body a good conductor of electricity?
The cells in the human body contain different ions (e.g. Cl- and Na+), which possess the tendency to conduct electricity.
Scientists have discovered a new substance on a distant planet. It has mass, definite volume, but cannot be compressed. What is its state of matter?
Liquid
Daisy poured some water into a glass. Then he dropped a marble into the glass of water. He noticed that the level of water rose. The rise in water level indicates _________.
the volume of the marble.
An atom of Sodium has an atomic number of 11 and a mass number of 23. This means that _____________.
Sodium has 11 protons, 11 electrons, and 12 neutrons
Susan drinks black coffee from a mug. The coffee has _____________. (properties)
no definite shape but has a definite volume.
Why are the elements in group 18 unreactive?
They have a full outer shell of electrons.
C-14 is an isotope used in the Carbon dating of dead objects due to which of the following reasons?
It is found in nature abundantly and in a definite ratio.
Dry ice is used in fire extinguishers. The dry ice is stored in the cylinder in a solid form. When sprayed on a fire it quickly changes into the gas known as Carbon Dioxide (CO2). What is this change of state called?
Sublimation