Endothermic and Exothermic
If a reaction feels cold, what type of reaction is it?
Endothermic
An atom has 6 protons and 8 neutrons. What isotope is this?
Carbon - 14
Balance: H₂ + O₂ → H₂O
2 H₂ + O₂ → 2 H₂O
What period and group is calcium (Ca) in?
Period 4, Group 2.
If a reaction feels warm, what type of reaction is it?
Exothermic
An atom loses 3 electrons. Explain what happens to its charge.
+3
Balance: Na + Cl₂ → NaCl
2 Na + Cl₂ → 2 NaCl
How many valence electrons does carbon (C) have?
4 valance electrons
Is burning wood endothermic or exothermic?
exothermic
An atom has 20 protons and 18 electrons. What is the charge?
+2
Balance: N₂ + H₂ → NH₃
N₂ + 3 H₂ → 2 NH₃
Identify an element in Period 2, Group 8.
Neon
A chemical pack gets cold when shaken. What type of reaction is this?
endothermic
What atom has an Atomic number: 6 and Mass number: 14. Is it an isotope, or ion?
Carbon, Isotope Carbon-14
Balance: K + O₂ → K₂O
4 K + O₂ → 2 K₂O
How many electron shells does potassium (K) have?
4 electron shells
A reaction needs constant heat to keep going. What type is it and why?
Endothermic
An atom has 17 protons and 18 electrons. Is this a cation or an anion?
Anion
Balance: CH₄ + O₂ → CO₂ + H₂O
CH₄ + 2 O₂ → CO₂ + 2 H₂O
What is the group number of an element with 7 valence electrons?
17 Halogen Group