Chemistry Challenge for Tenth Graders

What is the result of a chemical reaction where the atoms in the reactants rearrange to form new products?

• Physical change

• Chemical change

• Phase transition

• Conservation of mass

Which subatomic particle is not found in the nucleus of an atom?

• Proton

• Neutron

• Electron

• Quark

What trend in atomic radius occurs as you move down a group in the periodic table?

• It decreases

• It increases

• It remains constant

• It fluctuates unpredictably

What type of bond is formed when two atoms share electrons?

• Ionic bond

• Covalent bond

• Metallic bond

• Hydrogen bond

Which of the following is a property of acids?

• They turn litmus paper blue

• They have a pH greater than 7

• They taste bitter

• They react with metals to produce hydrogen gas

What is the general formula for alkanes in organic chemistry?

• CnH2n+2

• CnH2n

• CnHn

• CnH2n-2

In a balanced chemical equation, what must be equal on both sides of the equation?

• The number of molecules

• The number of atoms for each element

• The total mass of reactants and products

• Both B and C

Which element has the highest electronegativity?

• Hydrogen

• Carbon

• Fluorine

• Oxygen

What is the term for the outermost electrons in an atom that are involved in chemical bonding?

• Core electrons

• Valence electrons

• D-shell electrons

• Neutron cloud

Which of the following is not a characteristic of ionic compounds?

• High melting points

• Conduct electricity when dissolved in water

• Usually formed between metals and nonmetals

• Share electrons equally between atoms