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science questions
Chapter 17 questions
Question | Answer |
---|---|
90 of the elements in the periodic table are ______. the others are man-made(synthetic) in labortories. | occur naturally |
What are the 5 most common things that make up living things? | oxygen, carbon, hydrogen, nitrogen, and calcium |
What is the lightest element in the periodic table? | Hydrogen |
Atoms moves fastest in... | gases |
Who had the first idea of atoms? | the Greeks |
Whats the Brownian Motion? | its the constant jiggling of particles just large enough to be seen; evidence that atoms exsist from the motion or neighboring atoms and molecules. They bump into the larger particles we can see |
What consists of two or more atoms that bond together by sharing electrons? | molecules |
Whats the difference between atoms and molecules? | atoms are single pieces and molecules and two or more atoms |
H2O is a ... | compound |
A substance that is made of atoms of different elements combined together is a... | compound |
What does a chemical formual show? | it shows the symbols of elements presents and the number of atoms of each element |
What kind of particles and their charges are nucleons? | protons (positive) and neutrons (neutral) |
What is the atomic number? | the number of protons; how the elements are arragned on the periodic table |
what is an example of an isotope? | C-14, the most common is C-12 |
Isotopes have the __________ as a regular atom but a different ______________. | atomic number; mass number |
Isotopes have the same number of _______________ as a regualar atom and a different number of ___________________. | protons; neutrons |
What is the nucleus made of? | (nucleons) protons neutrons |
What charge does electrons have? | negative charge |
When an atom no longer has the same amount of protons and electrons, what does the atom become? | an ion |
How many electons can the 1 shell hold? | 2 electrons |
The second shell can hold up to ________ electrons | 8 |
how many eletrons can the outer shell hold? | no more than 8 |
What is a covalent bond? | when 2 atoms share electrons from the outer shell; (co-share; valent- outershell)(connect together) |
What is an ionic bond? | when electrons are transferred between atoms; when the electrons transfer they become ions (give away and arent connected) |
What does a column show on the periodic table? | how many outer electrons that are the elements in that column... example...Li is in the first collumn so it has ONE electron on the outershell |
What are the 3 most common phases of matter? | solid, liquid, gas |
What phase of matter only exsists in very very high temperatures? | plasma |
Where can plasma most commonly be found | in the stars |
freezing point | 0 C |
melting point | 0 C |
boiling point | 100 C |