Question

1. what type of elements are known to be able to conduct heat and electricity only under certain conditions, with the most famous member being silicon and makes up 28% of the earths crust? a. metals b. metalloids c. non - metals d. halogens 18) these elements are mostly solid, are shiny, good conductors, and are both malleable and ductile. a. metals b. non - metals c. noble gases d. halogens 19) what subatomic particle is responsible for the bonding between atoms, has a negative charge, and orbits the nucleus at different energy levels? a. protons b. neutrons c. electrons 20) how many protons are in this neutral atom? a. 10 b. 20 c. 30 d. 40

Explanation:

• 17: Metalloids have properties between metals and non - metals. They can conduct heat and electricity under certain conditions. Silicon is a well - known metalloid and makes up about 28% of the Earth's crust. Metals are generally good conductors without the "only under certain conditions" caveat. Non - metals are usually poor conductors. Halogens are a group of non - metals with specific chemical properties not related to this conductivity description.
• 18: Metals are mostly solid (except for mercury at room temperature), shiny (lustrous), good conductors of heat and electricity, malleable (can be hammered into thin sheets), and ductile (can be drawn into wires). Non - metals lack these physical properties (e.g., they are not malleable or ductile in the same sense). Noble gases are gases at room temperature and are inert. Halogens are non - metals with different chemical and physical characteristics.
• 19: Electrons are the subatomic particles with a negative charge that orbit the nucleus at different energy levels. They are involved in chemical bonding (e.g., in ionic bonding, electrons are transferred; in covalent bonding, electrons are shared). Protons have a positive charge and are in the nucleus. Neutrons have no charge and are also in the nucleus.
• 20: In a neutral atom, the number of protons is equal to the atomic number. For calcium (Ca), the atomic number is 20 (given in the periodic table notation). The mass number (40.08) is the sum of protons and neutrons, but the number of protons is directly given by the atomic number.

Answer:

1. B. Metalloids
2. A. Metals
3. C. Electrons
4. B. 20