SCIENCE MCQ
1) How many different elements are in a water molecule?
2
45) Why do nonpolar substances tend to boil at relatively low temperatures?
A) Not much heat is required to separate nonpolar molecules from one another.
65) An element will decay to an element with higher atomic number in the periodic table if it emits
A) a beta particle.
16) The fact that the air you breathe doesn't give off visible light indicates the electrons of its atoms are
A) in the ground state
58) There is a greater proportion of carbon-14 in
A) new bones.
14) The weight of matter comes mostly from its
A) protons.
50) The atomic number of an element is the same as the number of its
A) protons.
5) What makes an element distinct?
A) the number of protons
57) Pure elements can be transformed into entirely different elements. This statement at the present time is
A) true.
28) What is the difference between an element and a chemical compound?
B) An element consists of only one type of atom.
40) A molecule is
B) a group of covalently bonded atoms
64) When a nucleus emits a positron, its atomic number
B) decreases by 1.
17) Each vertical column in the periodic table corresponds to a
B) group.
22) As atoms get more massive, they become smaller in size because
B) more mass means more protons, which act to pull electrons in closer to the nucleus.
2) Which of the following are electrically neutral?
B) neutron
49) When a nucleus emits a beta particle, its atomic number
B) remains constant, and so does its mass number.
37) If magnesium ions have a 2+ charge and oxygen ions have a 2- charge, the compound magnesium oxide is correctly written
C) MgO
41) A neutral hydrogen atom can attract an additional electron
C) because the additional electron finds room in the valence shell.
24) During a chemical reaction
C) old atoms stick around merely switching partners.
8) In an electrically neutral atom, the number of protons in the nucleus is balanced by an equal number of
C) orbital electrons.
46) The alkali metals (group 1) tend to form 1+ ions while the alkali-earth metals (group 2) tend to form 2+ ions because
C) the charges of these ions is the number of valence electrons that may be lost.
Compared to the atoms that make up the body of an elderly person, the atoms that make up the body of a newborn baby are
C) the same age.
10) What is the total number of protons and neutrons in a water molecule?
D) 18
23) How is a physical change different from a chemical change?
D) The chemical identity of a substance is not altered during a physical change.
34) What elements tend to form ionic compounds?
D) elements found on opposite sides of the periodic table METAL AND NONMETAL
51) Different isotopes of an element have different numbers of
D) neutrons.
60) Most of the radioactivity we personally encounter comes from
D) the natural environment.
how to find electrons when given neutrons
atomic mass - neutrons=electrons
what three trons are the same
electron proton and atomic number
how to find neutrons for a element
find the atomic mass of the element and subtract the atomic mass by the atomic number
